Feature: Rewrite check kernel

[LordHepipud]

The current handling for compiling Icinga for Windows checks causes various issues in certain situations. These include:

• Wrongly detected units and therefor wrong conversion of values
• Negative thresholds sometimes not being applied properly
• Slow execution of check compiling
• Wrong report of warning/critical value comparison, determining if the thresholds are properly configured

To resolve this, the entire check kernel backend is re-written and redesigned with less overhead and proper evaluation.

Fixes #131
Fixes #435
Fixes #503
Fixes #528

[drapiti]

We have noticed on version 1.10 of the framework most likely a side effect of the slightly high consumption in certain moments and in any case much better than previous versions, however many checks timeout and go into an unknown state if there are few resources or the server is under load. They do recover however the monitoring and performance metrics have notable holes. Hopefully this can be addressed with the kernel rewrite. Another small step is required for the framework to be reliable on all server workloads. We have over 5k windows servers now with the framework so we were able to witness this behaviour on a consistent basis.
Cheers.