python: add .gitignore

python: add .gitignore

Ignore *Python* build and package output (build, dist, qemu.egg-info);
these files are not created as part of a QEMU build. They are created by
running the commands 'python3 setup.py <sdist|bdist>' when preparing
tarballs to upload to e.g. PyPI.

Ignore miscellaneous cached python confetti (mypy, pylint, et al)

Ignore .idea (pycharm) .vscode, and .venv (pipenv et al).

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Message-id: 20210527211715.394144-30-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>