Propagate Gitaly feature flags
Fixes #129 (closed).
We get the flags from here https://gitlab.com/gitlab-org/gitlab/-/blob/f5efd46fb8b9d82268db226e5ffb2e0d38fe6dc0/lib/api/internal/kubernetes.rb#L36 and this func is here https://gitlab.com/gitlab-org/gitlab/-/blob/f5efd46fb8b9d82268db226e5ffb2e0d38fe6dc0/lib/feature/gitaly.rb#L16-29. I think the right thing to do is just to pass them through as they are to Gitaly. It handles them here https://gitlab.com/gitlab-org/gitaly/-/blob/56aa9a2196f0003bc011e4152bb093b8d32be83d/internal/metadata/featureflag/grpc_header.go#L81-86.
@8bitlife Hi, could you review this one please?