Support serving bare repositories

Created by: andir

On my Git host I've all the repositories in "bare" format. They have been created using git init --bare $name and thus do not have a .git folder within them. The repositories don't need a full checkout nor a .git folder when being accessed via SSH. Currently serving those repositories doesn't work as the check for .git folder within them fails.

On the filesystem the layout looks like this:

/data
/data/foo.git
/data/bar.git
/data/project1/zes.git
/data/project2/des.git
...

Ideally each of the repositories would appear with their name with the .git suffix stripped (foo, bar, project1/zes, ...).

Is this something you'd like in the upstream code base? I wouldn't mind trying to tackle the issue as the original code seems to have enough test coverage for me to be confident in not breaking stuff on the way.