Add optimizer for BBO

Ref: #578057

What does this MR do and why?

Following up !209791 (merged)

This MR makes sure the BBO framework leverage the existing database signals. It allows to stop or optimize the operation based on several heuristics.

Query plan

1. Create 10 more partitions using - query

   DO $$
   BEGIN
     FOR i IN 2..11 LOOP
       EXECUTE format('CREATE TABLE IF NOT EXISTS gitlab_partitions_dynamic.background_operation_workers_%s
         PARTITION OF public.background_operation_workers FOR VALUES IN (%L)', i, i::text);
     END LOOP;
   END
   $$;

2. Data population: Created 100000 records per partitions, with equal distribution between 5 tables and atleast 20% paused workers (10% with on_hold_until in the past and other 10% with on_hold_until in the future) - query.

   DO $$
   DECLARE
       i int;
       table_names text[] := ARRAY['users', 'projects', 'issues', 'notes', 'namespaces'];
       records_per_partition int := 100000;
       records_per_table int := 20000;
   BEGIN
       FOR i IN 1..11 LOOP
           INSERT INTO public.background_operation_workers (partition, organization_id, user_id, created_at, batch_size, sub_batch_size, interval, job_class_name, batch_class_name, table_name, column_name, gitlab_schema, status, on_hold_until, min_cursor, max_cursor)
           SELECT
               i,
               (i * 1000000) + rc,
               (random() * 1000000)::bigint,
               CURRENT_TIMESTAMP - (random() * interval '30 days'),
               1000,
               100,
               120,
               'BackgroundWorker',
               'BackgroundJob',
               table_names[((rc - 1) / records_per_table) + 1],
               'id',
               'gitlab_main',
               CASE WHEN (rc - 1) % records_per_table < (records_per_table * 0.1)::int THEN
                   2
               WHEN (rc - 1) % records_per_table < (records_per_table * 0.2)::int THEN
                   2
               ELSE
                   ((rc - 1) % records_per_table - (records_per_table * 0.2)::int) % 5
               END,
               CASE WHEN (rc - 1) % records_per_table < (records_per_table * 0.1)::int THEN
                   CURRENT_TIMESTAMP - interval '2 days'
               WHEN (rc - 1) % records_per_table < (records_per_table * 0.2)::int THEN
                   CURRENT_TIMESTAMP + interval '2 days'
               END,
               jsonb_build_array(1),
               jsonb_build_array(1000000)
           FROM
               generate_series(1, records_per_partition) AS rc;
           RAISE NOTICE 'Inserted % records into partition %', records_per_partition, i;
       END LOOP;
   END
   $$;

3. Generate some jobs

INSERT INTO background_operation_jobs (
    worker_id,
    organization_id,
    partition,
    worker_partition,
    created_at,
    started_at,
    finished_at,
    batch_size,
    sub_batch_size,
    pause_ms,
    status,
    attempts,
    metrics,
    min_cursor,
    max_cursor
)
SELECT 
    w.id,
    w.organization_id,
    1,
    w.partition,
    NOW() - (j || ' minutes')::interval,
    NOW() - (j || ' minutes')::interval,
    NOW() - ((j - 0.5) || ' minutes')::interval,
    1000,
    100,
    100,
    3,
    CASE WHEN random() < 0.1 THEN 2 ELSE 1 END,
    jsonb_build_object(
        'total_processed', (random() * 1000)::int,
        'duration_ms', (random() * 3600000)::int
    ),
    jsonb_build_array((j - 1) * 1000 + 1),
    jsonb_build_array(j * 1000)
FROM (
    SELECT id, organization_id, partition
    FROM background_operation_workers
    LIMIT 100
) w
CROSS JOIN generate_series(1, 100) AS j;

4. Query plan - not exactly the same as we can't identify the righ uuid to pick up

SELECT
    background_operation_jobs.*
FROM
    background_operation_jobs
WHERE
    background_operation_jobs.worker_id = '66846817-bb93-4510-a7e5-0b4f90af7f98'
    AND background_operation_jobs.finished_at IS NOT NULL
    AND (background_operation_jobs.status IN (3))
ORDER BY
    background_operation_jobs.finished_at DESC
LIMIT 10;
                                                                                     QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=259.54..259.54 rows=1 width=141) (actual time=2.005..2.009 rows=10 loops=1)
   Buffers: shared hit=336
   ->  Sort  (cost=259.54..259.54 rows=1 width=141) (actual time=2.004..2.005 rows=10 loops=1)
         Sort Key: background_operation_jobs.finished_at DESC
         Sort Method: top-N heapsort  Memory: 27kB
         Buffers: shared hit=336
         ->  Index Scan using background_operation_jobs_1_status_idx on background_operation_jobs_1 background_operation_jobs  (cost=0.29..259.53 rows=1 width=141) (actual time=0.217..1.983 rows=100 loops=1)
               Index Cond: (status = 3)
               Filter: ((finished_at IS NOT NULL) AND (worker_id = 'c6feed1e-7115-42f2-8e54-f7c191b47972'::uuid))
               Rows Removed by Filter: 11002
               Buffers: shared hit=336
 Planning Time: 0.204 ms
 Execution Time: 2.051 ms