Search for users to start a new DM.
Hooks up the create room UI to the matrix client to get
search results. Searches are debounced for 500ms and
only executed when 3 or more characters are entered.
Wrap the result state so we can distinguish between
"no results because we haven't searched yet" and
"no results because the API returned nothing", and
add a "No results found" message in the UI for the
latter case.
Closes#95
* Validate ids in constructors.
* Remove redundant `.value` usage in string interpolation.
* Make a distinction between `SessionId` and `UserId` in `TestData`.
* Implement room member list
* Move timeline initialization back to `TimelinePresenter`.
* Fix crash when the `innerRoom` inside a `RustMatrixRoom` is destroyed but `syncUpdateFlow` is still running.
* Address review comments
