Feature request: Add room icon overlay to indicate federated/federation disabled/bridged

### Description

It is possible to invite rooms not located on locally hosted home server. In this case any local user posting in that room is posting to a server outside of local administrative control.
Suggestion: Add an icon overlay to non-local rooms indicating that they are remotely located.
Perhaps include a popup warning on initial room invite to highlight the possible leak of information.

### Steps to reproduce
n/a

### Version information
Both browser and desktop