Add local git config options in the forms

[jfouret]

Hi,

This is a small feature request,

It would be beneficial to add local configuration option for the repo in the form such as pull.rebase and pull.ff.

I have read several issues that would be fixed with that.

Bests,

[zaz-wk]

Having trouble with "divergent branches" which I can't solve. Running git pull.rebase or git pull.ff is not an option, because I can't run git on the server. Therefore, I support @jfourets request.
I'd also appreciate to have the option to switch off sparse checkout in the form.