BUG: Find consistent Python interp, headers, libs #0013794

When possible, get consistent version of the Python interpreter, headers path,
and library.

find_package(PythonLibs) internally calls find_package(PythonInterp QUIET) and
uses the resulting PYTHON_VERSION_MAJOR and PYTHON_VERSION_MINOR to prefer
these versions when looking for the header path and library.
The Python_ADDITIONAL_VERSIONS variable has priority over the interpreter
version.

Co-authored-by: Adam Wolf
Co-authored-by: Gert Wollny <gw.fossdev@gmail.com>
Merge topic 'different-python-header-libs-exe-0013794' into next

6b47af93 BUG: Find consistent Python interp, headers, libs #0013794