Draft: Add admin setting to restrict CI/CD Catalog publishing

What does this MR do and why?

This POC introduces an allowlist mechanism that enables administrators to control which projects can publish components to the CI/CD Catalog.

Changes:

• Add ci_cd_catalog_projects_allowlist application setting to store allowed project paths as an array
• Create new "Catalog" section in admin CI/CD settings page with a text area for managing the allowlist
• Implement check_project_access validation in the release service to enforce the allowlist during component publishing

Behavior:

• When the allowlist is empty (default), all projects can publish
• When populated, only projects whose full_path matches an entry in the allowlist can publish to the Catalog
• Projects not in the allowlist receive an error message when attempting to publish

This POC is intentionally incomplete:

• No tests included
• No documentation
• Missing UI changes (e.g., disabling the "Set component project as a CI/CD Catalog project." toggle)

References

Catalog enhancement - allow administrator to re... (&14060)

Screenshots or screen recordings

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.