Minor fixes for the room directory
Here are some fixes for some visual bugs in the new room directory:
-
The "Join" button should not be blue -
There should not be a placeholder for the room topic if a room doesn't have one -
The number of users should be centered like the text in the "Join" button -
The button border should be in a CSS class and not a separator -
Rooms with no avatar should have one automatically generated
See #221 (closed)