Squashed commits:
[42e45fc] Even more tweaks following code review
[5dcd5be] Add swift-algoritms and switch bubbling detection to its `chunked` method
[4ac70ed] Move the groupBy implementation to Collection instead of Array
[6aeffc3] Tweaks following code review
[0ca5ac2] Bubbles working again, grouping computed closer to the UI level
[3a66030] Refactor how timeline items are built in the RoomTimelineController
[57d51e9] Remove grouping from timeline items
[8608950] Remove the RoomTimelineViewFactory, update the GroupRoomTimelineView
[9e52e61] Add array grouping extension, unit tests and switched the timeline controller to it
[7d213a1] First attempt
[90bb1d7] Remove now unused `RoomTimelineController` `updatedTimelineItem` calback
