These changes make the navigation and status bar accessible from within fullscreen applications by allowing the user to tap on the top or tap or drag on the bottom of the screen.
Also, since the top panel is now over top of all fullscreen applications, this moves the action drawer swipe area back into the status bar.

This merge request implements a more mobile optimized solution for popup notification.
-
The current controls are:
- Swipe up to move the notification to the notification center.
- Swipe left/right to dismiss the notification entirely.
- If multiple popup notifications are grouped together, tap on the bottom area to view them in a expanded view.
What still needs to be done:
- ~~For notification without a default action, tapping on them should probably open up the associated app.~~ Note: I think I will add this in a separate merge request as it probably should be the case regardless if the notification is a popup
- ~~Swiping down on a notification currently does nothing. Maybe we should map this to a notification action?~~ Note: I have some ideas I will try later, though for now, I will leave this action blank
- ~~The expanded view of notifications should be able to be dismissed by swiping up/down on the top/bottom of the list.~~ Note: Added
- Investigate further into how to remove the current desktop popup notifications.
- ~~Code clean up.~~ Note: The code is at least a bit better
Single popup notification:

Multiple popup notifications:

Multiple popup notifications in the expanded view:

Any feedback would be greatly appreciated.
Fixes: https://invent.kde.org/plasma/plasma-mobile/-/issues/274
Any feedback on these changes would be much appreciated.


Change Log:
- NanoShell FullScreenOverlay was changed to a LayerShellQt Window to keep it on the top layer and to prevent the popup from obsorbing all touch inputs.
- New animations were added to the volume popup.
- User can now change the volume by touching and dragging on the popup
- The mute button on the popup was fixed
- Mute buttons were added next to the volume sliders in the AudioApplet page
- Volume icons now dynamically update to the volume level
- Visual design adjustments
This allows us in the future to use mobileshell without having the WindowUtil singleton loaded (which does a bunch of wayland calls that aren't necessary for most applications).
Move from a C++ library + QML plugin to a QML plugin only for simplicity, since the homescreen switching architecture will be done from Plasma, and so use of the shell library only needs to be from QML.