Add config option to disable updating of server info
By default, git-repack(1) and git-receive-pack(1) both generate server information that was in the past used by the dumb HTTP transport. This transport isn't used much nowadays anymore, which makes generating the server info a moot point. As part of https://gitlab.com/gitlab-org/gitlab/-/issues/351415#note_830077042 we noticed that the generated data is really out of control though: we have more than 35GB of info/refs
in a single ref which otherwise is only about 5GB in size.
While git-receive-pack(1) can be told already to stop generating this data, git-repack(1) can't. We should thus add a new config option to disable the generation. Cleanup of old stale data is tracked in gitaly#4027 (closed).