Add a periodic job fast forwarding release-4.x to community-4.x

This story covers adding a periodic job through the release repo running against the WMCO repo to fast-forward the latest commits on current release(ex: release-4.12) to the latest community branch(ex: community-4.12). This will avoid opening manual backports to the latest community branch and help with our goal to release a community operator every sprint.

Acceptance Criteria:

• Post-submit job for fast-forwarding community-4.13 from master
• Post-submit job for fast-forwarding community-4.12 from release-4.12
• Periodic job running daily to test OKD for community-4.12 and community-4.13 branches
• Slack notifications for failed/errored periodic jobs