955706 - system group actions - updates to support pulpv2

This commit contains several changes to allow katello
to support system group actions with pulp v2.  The primary
intent is to support the same functionality that was
available with katello on pulp v1.

The following is a high-level summary:

1. support for:
   pkg install/update/remove
   pkg group install/update/remove
   errata install

2. support importing gpg keys on client
   during install/update actions

3. update the task status and event history
   to support the new formatted responses
955706 - removed lines that were commented out
955706 - regenerating vcr cassettes
Merge pull request #2476 from bbuckingham/955706-2

955706 - updates to renable support for system groups