- document new variable from the CMake module
- use it in libcalamaresui to simplify #include'ing the
header for the "all" extension.
Suggested by Denis Proskurin.
- don't log when libs not found
- log that it's the Python libraries version (not Python itself)
- fix RE that was getting the wrong results for maj.min
- replace weird distinction between 3.0 and 3.2 by searching once
- prefer 3.2
- also look for suffixed versions (PythonXY) besides the Python3 suffix
FIXES#857