Absorb grpc-proxy into Gitaly
This change absorbs the previously vendored library grpc-proxy into the Gitaly project for breaking changes needed for Praefect requirements. There were slight modifications needed to make the project work within Gitaly:
- Go import paths were rewritten to refer to the new Gitaly location
- Test service code was moved to
testdata
folder to prevent CI linter warnings - CI-lint overrides were added to exclude inherited technical debt (see follow up issue #1663 (closed))
- Removal of unused/ineffective code detected by linter
Edited by GitLab Release Tools Bot