Manage existing room aliases on Element X

### Your use case

#### What would you like to do?
manage room + space aliases on my phone
#### Why would you like to do it?
- aliases remain taken even when I am the last user to leave a room, polluting the namespace forever.
- i might also want to customise it to be easier to memorise and type when referring to it (with autocomplete in the composer).
- i need to add a new alias on another server if the server hosting the existing alias disappears or only resolves unreliably.
#### How would you like to achieve it?
at worst, similar to Element Web UX

### Have you considered any alternatives?

_No response_

### Additional context

_No response_

Start by reviewing the Element Web UX, as suggested in the issue, and map the corresponding Element X phone workflow for room and space aliases. Define behavior for viewing, customizing, and adding aliases on another server; done means the listed use cases have an agreed, usable mobile workflow.

Written by the indexing model from the issue text.