* Theme refactoring
* disable the automatic tinting of surfaces with elevation in dark mode
* make the media warning visible again with the dark theme
* fix nav bar on api 27+
* use correct color for all media warnings
* Issue tuskyapp#762 add clear notifications button to the top of the Notifications adapter
* Issue tuskyapp#764 add the notifications filter
* Update notifications top bar buttons
* Replace PopupMenu with PopupWindow. Save notifications filter to the account table
* Disable hide top bar on empty content at the notification screen
* Add app bar behavior to the sw640 notification layout
* Fix issue with click on top notification tab
