[Devops Adoption] Add Vulnerability Management metric for Devops Adoption API

What does this MR do?

Add Vulnerability Management metric for Devops Adoption API

Migration output

== 20210713144637 AddVulnerabilitiesCreatedAtIndex: reverting =================
-- transaction_open?()
   -> 0.0000s
-- indexes(:vulnerabilities)
   -> 0.0209s
-- remove_index(:vulnerabilities, {:algorithm=>:concurrently, :name=>"idx_vulnerabilities_partial_devops_adoption"})
   -> 0.0038s
== 20210713144637 AddVulnerabilitiesCreatedAtIndex: reverted (0.0265s) ========

== 20210713135152 AddDevopsAdoptionVulnerabilityManagementUsedCount: reverting
-- remove_column(:analytics_devops_adoption_snapshots, :vulnerability_management_used_count, :integer)
   -> 0.0059s
== 20210713135152 AddDevopsAdoptionVulnerabilityManagementUsedCount: reverted (0.0083s)

== 20210713135152 AddDevopsAdoptionVulnerabilityManagementUsedCount: migrating
-- add_column(:analytics_devops_adoption_snapshots, :vulnerability_management_used_count, :integer)
   -> 0.0060s
== 20210713135152 AddDevopsAdoptionVulnerabilityManagementUsedCount: migrated (0.0060s)

== 20210713144637 AddVulnerabilitiesCreatedAtIndex: migrating =================
-- transaction_open?()
   -> 0.0000s
-- index_exists?(:vulnerabilities, [:project_id, :created_at], {:where=>"state != 1", :name=>"idx_vulnerabilities_partial_devops_adoption", :algorithm=>:concurrently})
   -> 0.0307s
-- add_index(:vulnerabilities, [:project_id, :created_at], {:where=>"state != 1", :name=>"idx_vulnerabilities_partial_devops_adoption", :algorithm=>:concurrently})
   -> 0.0167s
== 20210713144637 AddVulnerabilitiesCreatedAtIndex: migrated (0.0508s) ========

Index creation takes 1 minute in #database-lab so I believe it's ok to keep it in migrate folder.

Query explain

https://console.postgres.ai/gitlab/gitlab-production-tunnel-pg12/sessions/5161/commands/18237#visualize-depesz

 Aggregate  (cost=1826.63..1826.64 rows=1 width=8) (actual time=8.843..8.844 rows=1 loops=1)
   Buffers: shared hit=4982 read=263
   I/O Timings: read=3.897 write=0.000
   ->  Nested Loop Semi Join  (cost=0.99..1826.63 rows=1 width=0) (actual time=0.273..8.837 rows=4 loops=1)
         Buffers: shared hit=4982 read=263
         I/O Timings: read=3.897 write=0.000
         ->  Index Only Scan using projects_pkey on public.projects  (cost=0.56..1361.60 rows=654 width=4) (actual time=0.126..3.452 rows=652 loops=1)
               Index Cond: (projects.id = ANY ('{278964,11520423,11574953,13348998,13664986,14097509,14645774,14921629,15477483,15572444,15662771,15704782,16239404,16513043,16700143,17181705,17210811,17743501,18925373,18977208,19042106,19402176,19532875,20401626,20867992,21224328,21483460,21734866,21740210,22133520,22907418,23601234,23944319,24134396,24200638,24763979,25534115,26630862,24693199,25567144,13083,13764,14022,14288,14289,16648,19776,20085,20086,20699,23081,27468,27470,27726,29286,32732,36743,72724,74823,83282,95156,98024,116212,140724,143237,145205,150440,227582,250324,250833,278964,280425,375711,387896,430285,443787,444821,455030,480929,554859,593728,629054,629060,684698,730448,734943,747741,766015,818896,876090,887372,928825,931715,998792,1075790,1120019,1209837,1265999,1329047,1379171,1441932,1470839,1507906,1533158,1777822,1794617,1911766,1990920,2009901,2127625,2317465,2337675,2347063,2383700,2651596,2670515,2694799,2725567,2890326,2903741,2953390,3010986,3010998,3094319,3101096,3305972,3362933,3430480,3466815,3588247,3605985,3631141,3651684,3662568,3662668,3674569,3698388,3871132,3871556,3885956,3885980,3933206,3933372,3991945,4108541,4121724,4149988,4157550,4176070,4186738,4186742,4262096,4341757,4382108,4534254,4542834,4562632,4870361,4921652,4949400,5019307,5261717,5420758,5647182,5981322,6043225,6043227,6092883,6185025,6457868,6466002,7071551,7540679,7602162,7792567,7937396,8343284,8362868,8671969,8987255,9134345,9149724,9359704,9438583,9492132,9780400,9927571,10024275,10614162,10619765,10786772,10947578,11047304,11067315,11080193,11261137,11446522,11997420,12051824,12104213,12212610,12274094,12425329,13015884,13053017,13284652,13368043,13453461,13473820,13683636,13831684,13942461,13997108,14018700,14025202,14071101,14146123,14217204,14290884,14378900,14520336,14694517,14707715,14771920,14785608,14850988,15032634,15158038,15297693,15363819,15420077,15445353,15447440,15461649,15502498,15687385,15815706,15816248,15943672,16110032,16505341,16573099,16603968,16732333,16842968,17039597,17113313,17133307,17318793,17334694,17345914,17429946,17522813,17661412,17930014,18060348,18307741,18307889,18331927,18594323,18594390,18629149,18741849,18776356,18860383,18863350,18893322,18912995,18943607,19031064,19461377,19657914,19861191,20059805,20326496,20468480,20510065,20904766,21250701,21439066,21479995,21565866,21751536,21751817,21808150,21819002,21967079,21967100,22217400,22363055,22795840,22874770,23105702,23156104,23176166,23617987,23627092,23838512,23854438,24467497,24671550,24873101,25031023,25033712,25205782,25312761,25398815,25402115,25416006,25417540,25418438,25837735,25847700,25861038,25981420,26130408,26250592,26576566,26744820,27244047,27490309,22351703,9281155,16302012,17843116,15114652,19722963,19969997,20352787,15065439,16552062,16706750,17192985,19533665,20376798,4359271,7682093,14588374,19310217,20085049,8377576,10071001,10071132,19974437,22438483,25691329,17349153,13017970,13017990,13018017,16488249,16756957,18641703,22414284,19922160,13815397,21324924,21628863,23544263,5677844,10523039,14402567,15962657,16297627,19551890,20842531,22850480,24345542,9184510,10400718,11688089,14404642,15828516,19019153,21764500,22517790,15019630,21635031,22487050,23203100,23344605,23586678,10747057,13142177,21055520,18256369,21055609,9237774,12558964,13017629,16863027,17616536,18256375,25838334,25839455,25840330,25840667,27079314,19043830,21731412,21731462,22046463,22070439,22382594,22408078,22409005,22413375,25944737,19890267,23069693,23069956,23070140,23070164,23070377,23070395,23176783,23176971,23505725,23599168,24302484,24313398,24313598,24317064,24460210,24542363,24544020,24544330,25230764,25298439,25537666,25538517,25560556,25829938,26217586,26217656,26549908,26598766,26638651,26808701,26808774,26882341,26882878,26997949,21055409,3828396,6329679,7453181,11915984,14372596,15393051,16590122,17253921,18439881,18663049,18991900,21525059,23495190,21055344,19800404,21055767,20209910,22215226,22336999,22390221,20110067,20744986,15412762,15499610,19936368,13490286,13672316,13672681,13673582,13673632,13673686,13673757,13673934,13674085,13674136,13675927,13675979,13676002,13676032,13676096,13676142,13676188,13676249,13676309,13676350,13824926,16613296,16622651,16819118,16819125,16819131,16819134,16819140,16819151,16819248,17023897,17043690,17134833,17530059,17821569,17823896,18770944,18789638,18792504,19290493,19290857,19315261,20498312,23508645,17863546,19209142,19245461,17257555,21824450,24339834,20466430,17584993,24470059,16816732,17311004,17433833,18759998,18760252,19265543,19536993,20516845,20747799,20791019,20916876,21573386,21796485,22249364,22566258,22637103,23597027,23690656,23730491,23916841,24300893,24451242,24501533,25158783,25247374,26079419,26584477,26815390,27209445,19843335,20623750,22679171,22734535,26566881,27214210,27219974,27226337,27227767,27229445,6374580,6374588,6374596,22810929,22810940,22811022,23928229,17245095,17990319,18208929,18766749,18976211,19279270,19568296,19655424,19993243,20081132,20630561,20839085,21649753,22847718,23512541,23526204,25969582,18855526,27051617,27051800,27286937,27484836,27484846,27484871,24907469,25216298,27494514,26615930,26615960,26616051,26616061,26616069,26698878,26699071,26699200,26710947,27209463,27220296,27221011,27456355,27456706,27456810,27457647,18899486,27260823,27261025,21573444,23101765,23740056,27213646,27327788,18256394,13954053,14130725,16549277,21486653,18899500,22848448,9172481,10947320,12507547,15486630,15926775,20360386,14392833,16913647,18156681,18875792,19028203,19720958,22130851,22433156,23345837,12138769,12959103,13327609,13437682,15710326,16466244,17966464,20107267,25891188,18406509,18922546,18650560,18766720}'::integer[]))
               Heap Fetches: 60
               Buffers: shared hit=3283
               I/O Timings: read=0.000 write=0.000
         ->  Index Only Scan using tmp_index2 on public.vulnerabilities  (cost=0.43..4.95 rows=16 width=8) (actual time=0.008..0.008 rows=0 loops=652)
               Index Cond: ((vulnerabilities.project_id = projects.id) AND (vulnerabilities.created_at >= '2021-06-01 00:00:00+00'::timestamp with time zone) AND (vulnerabilities.created_at <= '2021-06-30 00:00:00+00'::timestamp with time zone))
               Heap Fetches: 0
               Buffers: shared hit=1699 read=263
               I/O Timings: read=3.897 write=0.000

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Related to #328036 (closed)