python-common: update CMakeLists.txt to optionally use new packaging

Add support for invoking the new pep517 based packaging mode added
in a previous commit. Because this approach will not work on older
distros and there seems to be spotty support for the new packging
form on debian/ubuntu (when nested within a additional layer like
CMake) I am choosing not to enable the new stuff by default.

View with `git diff -w`

Signed-off-by: John Mulligan <jmulligan@redhat.com>