Related to https://codeberg.org/Codeberg/Community/issues/1944
* Allowed the githubdownloaderv3 to know whether issues and, or PRs are requested to migrate
* Used this information to decide to filter for "/pulls/" or "/issues"
* Or not to filter at all if issues == true && prs == true
* Added isolated test for the downloader and for the uploader
* Created a new test_repo in github.com/forgejo and set it up properly together with @Gusted
* Updated github_downloader_test with the new URLs and test data from the repo
* Recorded the API calls for local testing
* Added a minimal gitbucket test (which uses the github downloader under the hood)
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/8892
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: patdyn <patdyn@noreply.codeberg.org>
Co-committed-by: patdyn <patdyn@noreply.codeberg.org>
