Force partition attachment to happen during the weekend

What does this MR do and why?

gitlab:db:reindex is executed during the weekends and we can hook into it to execute our changes for finishing the partitioning of ci_builds.

How to set up and validate locally

This can be tested using a thin clone:

GITLAB_SIMULATE_SAAS=1 CI_DATABASE_URL='postgresql://user:password@127.0.0.1:port/gitlabhq_dblab' bin/rails runner "Feature.enable(:attach_ci_builds_partition); Gitlab::Database::CiBuildsPartitioning.new.execute"

Running \d+ p_ci_builds will show ci_builds as a partition to p_ci_builds:

Partitions: ci_builds FOR VALUES IN ('100')

the CI_DATABASE_URL can be generated using pgai cli

[1] pry(main)> Gitlab::Database::CiBuildsPartitioning.new.execute
  Gitlab::Database::PostgresPartition Exists? (192.5ms)  SELECT 1 AS one FROM "postgres_partitions" WHERE "postgres_partitions"."parent_identifier" = 'public.p_ci_builds' AND "postgres_partitions"."identifier" = 'public.ci_builds' LIMIT 1 /*application:console,db_config_name:ci,console_hostname:rocket-sled.local,console_username:marius,line:/lib/gitlab/database/ci_builds_partitioning.rb:66:in `block in already_attached?'*/
  Gitlab::Database::PostgresAutovacuumActivity Exists? (184.3ms)  SELECT 1 AS one FROM "postgres_autovacuum_activity" WHERE (schema = current_schema()) AND "postgres_autovacuum_activity"."table" IN ('ci_pipelines', 'ci_stages', 'ci_builds', 'ci_resource_groups') LIMIT 1 /*application:console,db_config_name:ci,console_hostname:rocket-sled.local,console_username:marius,line:/lib/gitlab/database/ci_builds_partitioning.rb:74:in `block in vacuum_running?'*/
  TRANSACTION (174.8ms)  BEGIN /*application:console,db_config_name:ci,console_hostname:rocket-sled.local,console_username:marius,line:/lib/gitlab/database/with_lock_retries.rb:172:in `execute'*/
   (176.3ms)  SET LOCAL lock_timeout TO '10000ms' /*application:console,db_config_name:ci,console_hostname:rocket-sled.local,console_username:marius,line:/lib/gitlab/database/with_lock_retries.rb:172:in `execute'*/
   (361.3ms)  SET LOCAL statement_timeout TO '11s'; LOCK ci_pipelines, ci_stages, ci_builds, ci_resource_groups IN ACCESS EXCLUSIVE MODE; DROP TRIGGER IF EXISTS ci_builds_loose_fk_trigger ON ci_builds; ALTER TABLE p_ci_builds ATTACH PARTITION ci_builds FOR VALUES IN (100); ALTER SEQUENCE ci_builds_id_seq OWNED BY p_ci_builds.id; ALTER TABLE p_ci_builds DROP CONSTRAINT partitioning_constraint; CREATE TRIGGER ci_builds_loose_fk_trigger AFTER DELETE ON ci_builds REFERENCING OLD TABLE AS old_table FOR EACH STATEMENT EXECUTE FUNCTION insert_into_loose_foreign_keys_deleted_records(); CREATE TRIGGER p_ci_builds_loose_fk_trigger AFTER DELETE ON p_ci_builds REFERENCING OLD TABLE AS old_table FOR EACH STATEMENT EXECUTE FUNCTION insert_into_loose_foreign_keys_deleted_records(); /*application:console,db_config_name:ci,console_hostname:rocket-sled.local,console_username:marius,line:/lib/gitlab/database/ci_builds_partitioning.rb:23:in `block (2 levels) in execute'*/
  TRANSACTION (174.8ms)  COMMIT /*application:console,db_config_name:ci,console_hostname:rocket-sled.local,console_username:marius,line:/lib/gitlab/database.rb:401:in `commit'*/
   (175.5ms)  RESET idle_in_transaction_session_timeout; RESET lock_timeout /*application:console,db_config_name:ci,console_hostname:rocket-sled.local,console_username:marius,line:/lib/gitlab/database/with_lock_retries.rb:172:in `execute'*/

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #382033 (closed)