I have a room with a custom type that's only for holding data, and
doesn't need to be shown in the room list. Currently the spec is a bit
vague about what clients should do, but hiding them is probably fine
for now.
(cherry picked from commit bb9ce117de)
- Clear out unused functions
- All functions are now static
This is because we pretty much always used it in the form:
```
EventHandler eventHandler(room, event);
eventHandler.function();
```
This simplifies it all to a single call.
This draws heavily on what @carlschwan did in network/neochat!1579 but I found it easier to start again and grab the bits as I needed them plus some other copying from what I did in the Space tree model.
From my current limited testing this seems to work nicely try and break it.
Make sure that the new rules for counting notifications for muted, mention and low priority rooms is applied consistently to the room list, space drawer and the task manager notification badge
implements #644
Change the LastActivity sort order to Activity and update to a more flexible way of sorting based on an order from model roles.
Add options to actually switch between Alphabetical and Activity
Based on some old work by @tdfischer
implements #103
