XS Add desired sharding key YAML config with backfill from ci_builds.project_id (6 tables)

What we need to do

These tables all have build_id, so we can add project_id and use ci_builds.project_id to backfill

• ci_builds_needs - #466438 (closed)
• ci_build_pending_states !171427 (merged)
• ci_build_trace_chunks !171601 (merged) && !173767 (merged)
• p_ci_build_trace_metadata !171604 (merged) && !174780 (merged)
• ci_builds_runner_session

Ci Job Variables has job_id, so we should also be able to backfill project_id from ci_builds.project_id

• ci_job_variables

How to do it

Once the designation is set in the db/docs/*.yml config file, ✨ automation ✨ will handle the rest.

ASK: Populate the db/docs file and then the automation will handle backfilling of the records. This is assuming the sharding key which it's backfilling is non-nullable. As is the case for ci_builds_needs. As it's backfilling from build_id which is already non-nullable.