[FL-2430] Automatic Desktop Locking (#1101)

* Add Auto Lock Time setting
* Update .gitignore
* Add value_index toolbox module
* Auto locking basic implementation
* Better AutoLock implementation, edge cases and cleanup
* Fix NULL pointer crash
* Turn off backlight shortly in locked mode
* Re-enable auto lock after pin lock
* Correctly handle start when pin locked
* Use timer to hide locked hint
* Use a single state variable instead of multiple bools
* Do not call update callback recursively
* Allow input when the Unlocked hint is shown
* Add a delay to backlight switch off while locking
* Better user input handling
* Switch backlight off after pin timeout
* Correct grammar in notification settings

Co-authored-by: あく <alleteam@gmail.com>

applications/desktop/views/desktop_events.h

@@ -38,4 +38,5 @@ typedef enum {
     // Global events
     DesktopGlobalBeforeAppStarted,
     DesktopGlobalAfterAppFinished,
+    DesktopGlobalAutoLock,
 } DesktopEvent;