Draft: POC Deduplicate intrinsic immutable data to Ci::JobInfo

What does this MR do and why?

This is a POC for moving immutable, intrinsic data into a new model Ci::JobInfo. Details:

1. The Ci::JobInfo model mirrors Ci::JobDefinition. The difference is that there is no separate association table (like ci_job_definition_instances). Instead, ci_builds has a direct belongs_to relationship to ci_job_infos.

2. Attempts to move the following columns from ci_builds into ci_job_infos:

• allow_failure --> Cannot move. This field is mutated when job transitions to failed.
• when --> Cannot move. This field is mutated in Ci::ProcessBuildService.
• scheduling_type
• stage_idx --> Indexed column; need to further evaluate query performance impact
• name --> Indexed column; need to further evaluate query performance impact

3. Attempts to move ci_build_names data into ci_job_infos.name column, which is set up with a search_vector column.

References

• Spike: Deduplicate intrinsic immutable data fro... (#577211)
• Spike: Deduplicate `ci_build_names` into one of... (#567704)

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Related to #577211