python/qemu: delint and add pylintrc

Bring our these files up to speed with pylint 2.5.0.
Add a pylintrc file to formalize which pylint subset
we are targeting.

The similarity ignore is there to suppress similarity
reports across imports, which for typing constants,
are going to trigger this report erroneously.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200528222129.23826-4-jsnow@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>