Port of server_environement

- Port of server_enviroment
- Renaming of server_enviroment_files to server_enviroment_files_sample
- Support of git in system info
I admit I don't know what's going on in detail, but I see in `test_default` a `model.create()`. Since checks should be safe at any time in the lifetime of a database, I was wondering whether fast_suite would be safer (it's executed only when you create the database).

Still, maybe I'm worrying too much, and we're in an uncommitted transaction anyway.

Thanks