WinGui: Build out code for active monitoring of storage and battery power on the...

WinGui:  Build out code for active monitoring of storage and battery power on the system.  (Similar to what the LinUI does)
- Automatic pause on "Low" or "Critical" battery alarms.  The % level is set in Windows power settings. Automatic Resume when AC returns, if it was paused by an alarm.
- Automatic encode pause when destination drive drops below 2GB.  (May make this a preference set later)
- Behaviour of pause queue on low disk space with a user defined level in preferences is unchanged.

#2109 #2181