Cleanup .zuul.yaml
Cleanup .zuul.yaml

Some cleanups:
* Use tox-lower-constraints template instead of individual jobs.
* Use cover template to run cover job only in check as voting.
* Sort list of templates alphabetically.
* Remove publish-to-pypi, it should stay in project-config (and
  the project-config change keeps it there).

Change-Id: I228b74e264db7a0f604b6d8b72b60d2c4ee854c5

openstack-infra/shade,openstack-infra/shade