Consider adding transient to room list buffer

I tried to set new matrix account with Ement as a new client. I was looking for operations like

- joining new room
- joining existing spaces
- create new space
- assign channel to space
- forgetting room
- setting notifications
- ....

There was helpful transient in room buffer but it required to open the buffer to perform operations which feels natural for room list buffer. I was able to do actions via M-x menu but it felt like I have broken set up and not as intended way.

Please, consider adding transient to room list buffer as well.