python_rules is completely broken when it comes to py2/py3 support.
Here, we replace it with native python rules from new Bazel versions [1] and rules_pip for PyPI dependencies [2].
rules_pip is somewhat little known and experimental, but it seems to work much better than what we had previously.
We also unpin rules_docker and fix .bazelrc to force Bazel into Python 2 mode - hopefully, this repo will now work
fine under operating systems where `python` is python2 (as the standard dictates).
[1] - https://docs.bazel.build/versions/master/be/python.html
[2] - https://github.com/apt-itude/rules_pip
Change-Id: Ibd969a4266db564bf86e9c96275deffb9610dd44
Serge Bazanski