pm:cpupower: Add SWIG bindings files for libcpupower

pm:cpupower: Add SWIG bindings files for libcpupower

SWIG is a tool packaged in Fedora and other distros that can generate
bindings from C and C++ code for several languages including Python,
Perl, and Go.

These bindings allows users to easily write scripts that use and extend
libcpupower's functionality. Currently, only Python is provided in the
makefile, but additional languages may be added if there is demand.

Added suggestions from Shuah Khan for the README and license discussion.

Note that while SWIG itself is GPL v3+ licensed; the resulting output,
the bindings code, is permissively licensed + the license of the .o
files. Please see
https://swig.org/legal.html and [1] for more details.

[1]
https://lore.kernel.org/linux-pm/Zqv9BOjxLAgyNP5B@hatbackup/

Suggested-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: John B. Wyatt IV <jwyatt@redhat.com>
Signed-off-by: John B. Wyatt IV <sageofredondo@gmail.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>