Add default labels to the merge request template [template only]

What does this MR do?

This MR adds the default labels to our MR template which makes it easier to track the MRs tagged for composition analysis work. It also adds some commented add label quick action lines. They are individually commented out so that you can highlight a single line and then use cmd+/ or ctrl+/ to quickly uncomment the line.

What are the relevant issue numbers?

N/A

Does this MR meet the acceptance criteria?

• [-] Changelog entry added
  • Not user facing feature.
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer