Per repo settings

[Sonny]

git has the concept of global and local settings git config --help
It looks like we should be able to store custom settings in the repo .gitconfig.

We can use that for title-length-hint and body-length-wrap .

This will let us have customizable settings per repo and add new ones #82

If we're going to do that, we might as well use the global .gitconfig instead of gsettings.

[Sonny]

Note that we will need rw on the file system for this. Which would solve #68 as well.