Keep track of our own profile

- download it when logging in
- given that we can't rely on profiles being enabled on the server ... we need to figure out when the profile is updated. Do we just fetch the profile every time we have a member event from join to join for ourselves? Yes, we can do this in afterSyncCompleted.

We can use this:
- show the name and avatar in the session list
- show it on top of the room list?