This MR does several things as a followup to
https://invent.kde.org/plasma/plasma-mobile/-/merge_requests/748:
- Use the word "lock" instead of "sleep" since we are locking the
device, not putting it to sleep
- Simplify usage by using existing MouseAreas instead of including our
own for this feature (I encountered several focus captures in folio that prevented the
SwipeArea from getting events)
The wallpaper blur causes extreme lag on the PinePhone, best to disable it for now by default, and hide it behind a setting. :C
https://invent.kde.org/plasma/plasma-mobile/-/issues/306
PS: is there a string freeze ongoing? this introduces 2 new strings
