Akuanduba

Fixes KeyError on Watchdog implementation for method "feed"

* Implements Linux Watchdog integration
* Fix minor linter complainings
* Removes legacy implementation of trigger
* Changes TimerCondition and Watchdog implementations using the threading.Timer class
* Implements new service that syncs system time with NTP server

This new trigger implementation allows you to attach multiple independent triggers to the framework, each one running its own stack of tools on every "StatusTrigger.TRIGGERED" event.

Besides, you can use three ways of comparing conditions now:
- AND
- OR
- XOR

The old implementation is still supported, but will be removed in the future