Workaround py36 encoding pip bug
Workaround py36 encoding pip bug

* ensures we add LC_ALL with UTF8 if not already set
* consolidate tox.ini indentation
* expose only generic py env on envlist
* sort envvars in tox

Change-Id: I3d01c5a19500db9a830c78193f82175b4c1d4361
Related: https://review.opendev.org/c/openstack/openstack-zuul-jobs/+/804890/

openstack/python-tripleoclient