* Give native strings to selinux library functions.
SELinux takes pathnames as native strings. That means we need to
convert to bytes on python2 and convert to text on python3.
Fixes#17155
* Read kitchen documentation, make module_utils params more like kitchen API
* Remove none nonstring strategy and add strict
* Raise TypeError on invalid nonstring strategy
* Document to_native()
* Make unittests for testing module_utils.text
