This allows users to mark all rooms in a space as read, matching similar
features found in other popular chat applications.
We opted to place the mark as read button at the top of the list instead
of next to the add user button like in room options since we felt this
will be the most-used button in the list.
Fixes#645.
Co-authored-by: Maple <mapletree.dv@gmail.com>
Co-authored-by: Maple <mapletree.dv@gmail.com>
