Add Time to Restore Service DORA metric

What does this MR do and why?

Adds 3rd DORA metric calculation so clients can make their DevOps processes better.

Database info

== 20220309100648 AddTimeToRestoreServiceDoraMetric: reverting ================
-- remove_column(:dora_daily_metrics, :time_to_restore_service_in_seconds, :integer)
   -> 0.0060s
== 20220309100648 AddTimeToRestoreServiceDoraMetric: reverted (0.0088s) =======

== 20220309100648 AddTimeToRestoreServiceDoraMetric: migrating ================
-- add_column(:dora_daily_metrics, :time_to_restore_service_in_seconds, :integer)
   -> 0.0080s
== 20220309100648 AddTimeToRestoreServiceDoraMetric: migrated (0.0080s) =======

== 20220309154855 AddIndexOnIssuesClosedIncidents: reverting ==================
-- transaction_open?()
   -> 0.0000s
-- indexes(:issues)
   -> 0.0516s
-- remove_index(:issues, {:algorithm=>:concurrently, :name=>"index_on_issues_closed_incidents_by_project_id_and_closed_at"})
   -> 0.0050s
== 20220309154855 AddIndexOnIssuesClosedIncidents: reverted (0.0730s) =========

== 20220309154855 AddIndexOnIssuesClosedIncidents: migrating ==================
-- transaction_open?()
   -> 0.0000s
-- index_exists?(:issues, [:project_id, :closed_at], {:where=>"issue_type = 1 AND state_id = 2", :name=>"index_on_issues_closed_incidents_by_project_id_and_closed_at", :algorithm=>:concurrently})
   -> 0.0780s
-- add_index(:issues, [:project_id, :closed_at], {:where=>"issue_type = 1 AND state_id = 2", :name=>"index_on_issues_closed_incidents_by_project_id_and_closed_at", :algorithm=>:concurrently})
   -> 0.0196s
== 20220309154855 AddIndexOnIssuesClosedIncidents: migrated (0.1042s) =========

Index creation took 29minutes

Query explain: https://console.postgres.ai/gitlab/gitlab-production-tunnel-pg12/sessions/9118/commands/32246#visualize-depesz

Screenshots or screen recordings

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

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Related to #299096 (closed)