Move app_utils.py

I've moved `client/modules/app_utils.py`  to `client/app_utils.py` . This module does not have a `WORDS` constant and thus does not belong into that folder.
Moving this above the `conversation` import was neccessary because it imports `notifier`, which then [imports the Gmail module](https://github.com/jasperproject/jasper-client/blob/7647492c5839c944a510590502dcb28d58b73fae/client/notifier.py#L3), which uses `app_utils.py`.

In Jasper v2.0, I hope we can get rid of all this `sys.path` manipulation completely, but right now, we'll have to stick with it because we can't expect thrid party modules to use the correct import path (`import client.foo` instead of just `import foo`).