added profiles controller test and cleaned up around profiles controller

added profiles controller test, localised category action notice, deleted unused code in routes.rb, added test helper option for authorisation with devise gem, changed name of self-defined sign in helper method to distinguish from devise sign in method, adapted existing tests to new sign in method, deleted unused code in profiles_controller, added registrationController to redirect to all profiles after profiles deletion, removed error in admin comment action in admin profiles controller.