Draft: add manage.py to autodoc path

I'm trying to add manage.py to the conf.py path so that we can document all of its methods in a reference doc. These commands all seem to be installed in the api/funkwhale_api/cli folder, but when I try to add this as a path it just returns:

WARNING: autodoc: failed to import method 'users.create' from module 'cli'; the following exception was raised:
No module named 'cli'

The aim is to be able to create method documentation using the .. automethod:: function. This way we can keep everything up-to-date with changes to the script.