Remove CLI testing once and for all

The cli tests have been marked for removal for ~6 months and the
framework was the first thing included in tempest lib. There has
been more than enough time for all the projects to pick this up
in the client repos. So let's remove it all!

As part of this a couple of missing entries for tempest's
requirements.txt were found. These dependencies were being installed
by the clients so the fact they were missing was never noticed prior
to this. This commit also adds these missing entries back into the
requirements file.

Change-Id: I4f8638f1c048bbdb598dd181f4af272ef9923806

README.rst

@@ -18,7 +18,7 @@ Tempest Design Principles that we strive to live by.
   incorrect assessment of their cloud. Explicit is always better.
 - Tempest uses OpenStack public interfaces. Tests in Tempest should
   only touch public interfaces, API calls (native or 3rd party),
-  public CLI or libraries.
+  or libraries.
 - Tempest should not touch private or implementation specific
   interfaces. This means not directly going to the database, not
   directly hitting the hypervisors, not testing extensions not