Enable analyze for p_ci_builds_metadata

What does this MR do and why?

See #423959 (comment 1588358939)

This is related to #423135 (closed). We have built the feature to run regular analyze on partitioned tables so that Postgresql can use the table information to execute a better query plan. And now we want to register Ci::BuildMetadata and schedule to run the analyze weekly.

Screenshots or screen recordings

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Before	After

How to set up and validate locally

1. Open up Rails console and development logs:

   tail -f log/development.log
   rails c

2. Enable feature flag

   Feature.enable(:database_analyze_on_partitioned_tables)

3. Run sync_partitions

   ::Gitlab::Database::Partitioning.sync_partitions

4. Check if you can see the following output from Rails console or development logs

   ANALYZE VERBOSE "p_ci_builds_metadata"

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 #423135 (closed)