This is a publicly available view since people should be able to login
even without access to Plinth interface. Also avoid double login.
There should be no security risk in doing this.
- adapted all modules to not use views.ConfigurationView anymore
- removed templates that are not needed anymore
- no more implicit 'enabled' and 'get_status' functions in __init__.py files
- (more coherent/explicit use of Django functionality)
