[#1232] Add windows event log handler.

Problem description
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The logger only send error while initializing.

We want to allow windows logging after process was started and configured.


Changes description
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Add windows_eventlog log options.

Add custom WindowsEventLogHandler which translates our Chevah Events into WIndows Events.

In preparing for server integration I have added write code for log configuration.

I have also updated the default handlers functions as the previous code was in fact 2 functions in one. Also, I don't like the getattr(__srv_name__) part.

There is a single system test for Windows Event log. It will "polute" a bit windows event log with one entry for each run. Hope we can deal with that.


How to try and test the changes
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reviewers @alibotean 

Check that changes make sense.