* Add `DateTimeObserver` to rebuild the room summary data when the date/time changes.
* Add time changed action too, to trigger when the user manually changes date/time
* Fix timezone issue by adding `TimezoneProvider`, fix tests
* Create test for `DateTimeObserver` usage in `RoomListDataSource`
* Create aRoomListRoomSummaryFactory function.
* Improve test by faking the lastMessageTimestampFormatter
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Co-authored-by: Benoit Marty <benoit@matrix.org>
* Create `RoomLastMessageFormatter` to produce readable room summaries.
* Add unit tests using Robolectric, fix bugs
* Add changelog
* Move `RoomLastMessageFormatter` back to `impl` module, allow it to receive an `EventTimelineItem` instead of `MessageContent`.
