[DOP-26806] Merge ancestors and parents into one relation

[dolfinus]

Change Summary

Lineage endpoint returns parents relation with JOB-RUN and RUN-OPERATION relations. It also returns ancestor relations with JOB-JOB and RUN-RUN relations, but at OpenLineage and database level fields are called parent_run_id and parent_job_id. This can cause WTF reaction, so we need naming to be more consistent.

Related issue number

Checklist

• Commit message and PR title is comprehensive
• Keep the change as small as possible
• Unit and integration tests for the changes exist
• Tests pass on CI and coverage does not decrease
• Documentation reflects the changes where applicable
• docs/changelog/next_release/<pull request or issue id>.<change type>.rst file added describing change
  (see CONTRIBUTING.rst for details.)
• My PR is ready to review.

[github-actions]

Coverage Report •

File	Stmts	Miss	Branch	BrPart	Cover	Missing
data_rentgen/server/schemas/v1
lineage.py	137	4	2	0	97%	25, 34, 144, 189
TOTAL	7808	968	1226	211	87%