This change modernizes how testing is done in
networking-ovs-dpdk by droping legacy py 27 testing
and updateing how we use tox and sphinx.
With this change all testing is now done under python3.
While most testing had been moved to python3 already
his change simplifies the tox.ini file and raise the minium
version. Addtionally the setuptool classifier metadata has
been updateded to reflect that only python 3.6+ is supported.
This change also adops the openstack docs theme instead of the
legacy oslosphix theme and moves to build docs by directly invoking
sphinx. pdf-docs support is also added for parity with other projects
and bindep support for the pdf-docs target is added.
This change updates the zuul jobs to use the ussuri template.
This change updated the .gitignore to ignore addtional files that
are generated during testing.
This change updates the constratints url to use the web redirect
instead of the git repo and adds some TODOs for other cleanups.
Change-Id: I6b8a42666cd76d51041cf9f9f5ccb829adcf9b0d
c21b79250a