bulk-import-git-repos: align universal-pr with RHDH orchestrator e2e

[PatAKnight]

Summary

Aligns the universal-pr bulk-import workflow with Red Hat Developer Hub (RHDH) orchestrator e2e: backstage Postgres persistence, GitHub/GitLab token propagation (no GHTOKEN placeholder), org Quay image, and generator/manifest hygiene.

Changes

• Manifests (workflows/bulk-import-git-repos/manifests/):
  • Persistence → backstage-psql-secret / backstage-psql / backstage_plugin_orchestrator
  • Image → quay.io/orchestrator/serverless-workflow-bulk-import-git-repos:latest
  • Removed placeholder secret and GHTOKEN env from SonataFlow CR
  • Renumbered manifest files after secret removal (01–04)
  • Cleaned application.properties in ConfigMap (INFO logging, removed stale JDBC/auth comments)
• scripts/gen_manifests.sh: RHDH_PERSISTENCE profile (backstage Postgres, strip GHTOKEN/secrets, YAML cleanup)
• Makefile: bulk-import defaults (WORKFLOW_SUBDIR, RHDH_PERSISTENCE, manifest copy for CI)
• CI: fix workflow path trigger (workflows/bulk-import-git-repos/**)
• README / make.md: RHDH deploy and generator docs

Context

• Follow-up to RHIDP-9350
• RHDH e2e: installOrchestrator + oc apply manifests; no runtime Postgres patching

TODO: update the image tag from latest to one that is generated after this PR is merged (one more PR after this)