Add push_pipelines_for_job_token_allowed to ci_cd_settings

What does this MR do and why?

Adds the push_pipelines_for_job_token_allowed boolean column to project_ci_cd_settings.

This is a prerequisite database migration for the feature implementation in !243735 (closed), which allows projects to opt in to push pipelines triggered by a CI job token.

References

• Issue: #569974
• Feature implementation MR: !243735 (closed)