What does this MR do?
Upload Composer packages to packages page and add API endpoints
What are the relevant issue numbers?
See #15886 (closed)
Does this MR meet the acceptance criteria?
- Changelog entry added, if necessary
- Documentation created/updated
- 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
EE specific content should be in the top level
- Security reports checked/validated by reviewer