Merge branch 'support-gitaly-diff-service-diff-blobs-rpc' into 'master'

Support Gitaly's DiffService.DiffBlobs RPC

Closes #469161

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/160286



Merged-by: Peter Leitzen <pleitzen@gitlab.com>
Approved-by: Justin Tobler <jtobler@gitlab.com>
Approved-by: Peter Leitzen <pleitzen@gitlab.com>
Reviewed-by: Peter Leitzen <pleitzen@gitlab.com>
Reviewed-by: Ahmed Hemdan <ahemdan@gitlab.com>
Reviewed-by: Justin Tobler <jtobler@gitlab.com>
Co-authored-by: Ahmed Hemdan <ahemdan@gitlab.com>