WIP: timeout rework

[ZLLentz]

Previous behavior:

• The camviewer has 1 and 9 hour timeouts.
• After 1 hour, there is a pop-up that asks if you want to extend the timeout by 1 or 9 hours. Presumably this also appears after a 9 hour timeout.
• If a timeout expires, the gui stops getting images from the camera (but the camera continues to run), leaving a stale image.
• To re-establish connection, you can either swap the active cam back and forth or reconnect from the menu.

New behavior:

• Pop-up has been removed
• To reset the timeout: interact with the display in any way (click, type, etc.)
• Live-updating timeout display has been added
• The timer's starting value depends on the max display rate
• Max display rate can be changed live by the user
• 1 Hz = no timeout, ever
• 2-5 Hz = 7 days timeout
• 6-29 Hz = linear interp between 7 and 1 day
• 30 Hz+ = 1 day timeout
• If a timeout expires, rate drops to 1Hz until interacting with the GUI again (therefore: never a stale image if the real cam is running)
• pre-existing idle cli arg is now defunct (not sure what to do with it)
• min_timeout and max_timeout cli args added to help test the timeouts (timeouts in seconds, defaults to 1 day for the min and 7 days for the max)

I've been testing this via passing --min_timeout 10, then setting the rate to 30Hz, then watching the timeout apply after 10 seconds.