Cotanz: Activity feed button is always visible
The button should appear when a user enters a group, not already in the login screen
Users should also be able to 'stop' activity observation by clicking on the 'stop' button or by going to groups > action buttons (dropdown menu) > Stop Observing Activity.
Sketch for the menu (the extra item needs to be added):
I know the backend structure for this isn't there yet, but we should be able to toggle the activity feed in the frontend at least to not have the button be present all the time.