Improve day separator rendering in the timeline.
Use Today, Yesterday, and the name of the day if less than 7 days and do not render the year for the current year.
Improve date format for the media viewer.
Rework how date and time are computed.
ActionListView: Time can take more space, so update the layout.
* Open room member avatar in viewer.
The `MediaViewer` was extracted to its own library module.
* Update screenshots
* Restore KSP processor in `:libraries:mediaviewer:api`, this should generate Showkase components again.
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Co-authored-by: ElementBot <benoitm+elementbot@element.io>