More CI job refactoring

What does this Merge Request do and why?

⚠ This MR needs !2676 (merged) merged first.

This MR performs the following:

• Moves the test:yard CI job into the deploy stage as it's required by the deploy:pages.
• Only runs deploy:yard when the pipeline is for the default branch.
• Remove deploy- from the deploy:deploy-gitpod-workspace-image job.

Closes #1542 (closed)

Merge Request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise Issue to follow-up.
• Documentation added/updated, if needed.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.