Show Progress Bar for Git Clone

[clicky]

I work on a rather large repo, and it would be excellent if gitbutler reported a progress bar when performing a clone.

[Byron]

Thanks a lot for the suggestion!

Currently GitButler uses the Git program to perform the clone from which progress information can be parsed quite trivially from stderr. This could go alongside a tauri background task with/and/or events to deliver progress information to the frontend. I did have a link for background tasks at some point, but trying to find it now came up empty. However, it felt like progress could be implemented with that, at the time.