config: move various py templates to kallithea/templates/py/

For some reason, we had some python templates in kallithea/config .
kallithea.config is mainly the TG entry point, and thus a high level controller
thing - not a place to store templates.

Instead, use the templates directory and introduce a new py subdirectory.

With git hook templates in a templates directory, there is no need for tmpl in
the name.