[FL-2430] Automatic Desktop Locking

[gsurkov]

What's new

• Automatic desktop locking
• Customizable timeout
• Backlight switches off quickly in locked mode

Verification

• Go to Settings -> Desktop -> Auto Lock Time and set it to anything other than OFF
• Exit all applications (that means Settings too)
• Wait for the timeout to occur - Flipper should go to the locked mode
• Press random buttons in locked mode - display backlight should turn off after 1 second regardless of the backlight timeout setting
• Unlock Flipper, go to any application. Automatic locking should not occur when an applicaton is running.

Checklist (For Reviewer)

• PR has description of feature/bug or link to Confluence/Jira task
• Description contains actions to verify feature/bugfix
• I've built this code, uploaded it to the device and verified feature/bugfix

[github-actions]

Click here to flash the 60d68a16 version of this branch via WebUSB.