MAINTAINERS: Add Python library stanza

MAINTAINERS: Add Python library stanza

I'm proposing that I split the actual Python library off from the other
miscellaneous python scripts we have and declare it maintained. Add
myself as a maintainer of this folder, along with Cleber.

I will be actively working to add CI style guide checks, strict typing,
and an actual package infrastructure to this folder specifically which
differentiates it from loose, miscellaneous scripts which are generally
maintained by other individuals with subject matter expertise.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Cleber Rosa <crosa@redhat.com>
Acked-by: Eduardo Habkost <ehabkost@redhat.com>