built-in support for the `file` protocol

[Byron]

Currently gitoxide relies on shelling this out to the git upload-pack binary which isn't necessarily available on all systems. Instead, we must implement the server side of the fetch operation ourselves and use it.

Key Features

• [ ] Shallow support
  • Cargo supports shallow clones, and ideally these also work locally just like when using git
• [ ] Protocol V2
  • Probably V1 can be skipped

[NobodyXu]

Looking forward to this, it would be great if gix can support --local to use hardlinks to avoid copying .git or --shared to avoid copying any objects at all when dealing with local repositories.

[Byron]

I agree, and it's so low-hanging that I might even do that just to warm up with the topic.