Integrate more parts of CMK in GIT

In the global settings of our CMK site(s) we can activate the Setup GIT integration, which creates a local GIT repo in ~/etc/check_mk/.

Besides this we'd like to have something similar (most likely in another local repo, but who knows) for e.g. the user folders below ~/var/check_mk/web/, which contain the customizations of the current (and former) CMK users.

That's all for the while, but I'm open for suggestions of other things being needed in GIT repos (in order to have versioning, optional further integrate repo in my own centralized repos, etc.).