Add subcommands for create/revoke cert and add/remove user

* Break out cli from mtls core code
* Add support for retrieving CRL, Add user/remove user/admin via email
* Clean up cert checking, move to environ for enabling testing, add create/revoke certificate tests
* Begin work on Travis testing
* Break out lock, split dev and regular setup in Makefile
* Use pipenv run instead in make
* pull mtls-server version from environment in tests. Pre-pull mtls-server, add docker service
* Don't use format type string as python 3.5 doesn't support it