CE BE Improve admin licence page (Add GraphQL Metadata query type)

What does this MR do?

This is the frontend CE port to vue-ify the instance licenses page.

Without any EE license changes, this simply adds the metadata query that is the root for the license queries.

Please view the Table of MRs.

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer