Modify GitHub importer to be retryable
What does this MR do?
It allows GitHub import jobs to be retired correctly, first by not failing when it encounters the imported repo on disk, and second by caching the last page processed of every resource being imported to continue off that position on the next attempt.
Are there points in the code the reviewer needs to double check?
Why was this MR needed?
Screenshots (if relevant)
Does this MR meet the acceptance criteria?
- CHANGELOG entry added
API support added
Added for this feature/bug
- All builds are passing
- Conform by the merge request performance guides
- Conform by the style guides
Branch has no merge conflicts with
master(if it does - rebase it please)
- Squashed related commits together