This change adds the global zuul pep8 tox job, which runs both
bandit and pep8 using tox. This also removes the two other airship
specific lint-pep8 and bandit zuul jobs since they are both covered
by the default openstack global one.
Also cleaned up the tox.ini by moving the requirements into the
test-requirements.txt file.
Change-Id: Iccf6228ab9e6d621d3047994b3adc192d67273c9