Being able to sort for Rooms (Layoutsettings -> Filter)

### Your use case

#### What would you like to do?
I would like to see all rooms without Persons

#### Why would you like to do it?
Would be better to have an overview about the rooms

#### How would you like to achieve it?
Add to the Filter Option Rooms as an option

### Have you considered any alternatives?

Perhaps it would be good if you could choose/unchoose your favorite filteroptions, if you don't want certain filter options.

### Additional context

I am in german Matrix support rooms and every couple of days someone ask if you could get the old view with seperate view of rooms and person back.

When i tell them that there is in a Filter option in the Layoutsettings, they are very interested.
But there is Option missing to filter for rooms.

Perhaps this would move more people to the new app layout who changed back to the old app layout.

### Are you willing to provide a PR?

No

Start in the Android app's Layoutsettings → Filter UI and trace how the existing filter options are defined and applied. Add Rooms as a selectable filter so users can view rooms without persons, then verify the filter works alongside the existing options.

Written by the indexing model from the issue text.