* Kept old specific linter tox targets for backwards compatibility,
so developer can easily run a single linter if desired.
* Reused tox linters virtualenvs to avoid wasting space
* Moved linter config to their official location which enables
developer to call them in any way he wants (like his IDE)
* Updates yamllint to its newer version which supports strict
* Fixed yamllint errors
* Used parsable output format on yamllint which is more consistent
with other tools, being also recognized by IDEs and terminals.
Change-Id: I2bd44feb0a221dcd6f5402e070cf38b31fd8ac97
Depends-On: https://review.openstack.org/#/c/621930/
Story: https://tree.taiga.io/project/tripleo-ci-board/task/381