Add license management via merge request spec

What does this MR do?

Adds tests for approving and blacklisting licenses from the merge request.

Closes gitlab-org/quality/testcases#140 (closed) and gitlab-org/quality/testcases#141 (closed)

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content