codam.webgreeter v1.4.0

Reworked idle logout to work with codam-web-greeter v1.2.0 and later. A timestamp of when the screen was locked is now stored in /tmp and read by the codam-web-greeter to display remaining time before logout. We're no longer solely relying on xprintidle.

This release, combined with codam-web-greeter v1.2.0, essentially fixes the issue that caused the lock screen to be stuck when xprintidle reported an idletime of 0 seconds, even after having the screen locked for 42 minutes... when the codam-web-greeter expected the user to get logged out.