Engine: Fixes #3586 - Updates spec model tests and splits the
spec and test runs out again to prevent issues with the disable_glue_layers
functionality in the test/ tests.
Engine: UI: adding back the org aspect of a user's session

The code for the katello user's session was previously removed, since
the sessions (e.g. create/destroy) will be managed by the core app;
however, the session also included the ability to set the user's current
org.

Since orgs are currently handled differently between the core
app and the katello engine, this commit will add back the management
of the user's current katello org.  The goal in the future will be
to have a single org representation.
Engine: UI: Dashboard: fix loading of system group widget
Engine: models: fix some base class namespacing on models

Several of the models were referring to base class namespaces
(e.g. ::Provider); therefore, updating them to use the engine's
base.
Engine: UI: org-switcher: response should not be named object

E.g. the user object will not be returned as { 'user' : { ... } }
for the v2 api.
Engine: UI: fix ability to add/remove systems from system group
Engine: UI: Red Hat Repos: fix regression from moving to isolated namespace

Minor change that had gotten accidentally removed as part of
the move to using an isolated namespace.
Engine: Fixing navigation tests, refs #3585
Merge pull request #3343 from ehelms/engine-spec-models

Engine: Fixes #3586 - Updates spec model tests and splits the
Merge pull request #3349 from bbuckingham/engine-org_session

Engine: UI: adding back the org aspect of a user's session
Merge pull request #3350 from daviddavis/eng-nav-tests

Engine: Navigation test fixes
Merge pull request #3348 from bbuckingham/engine-random_fixes

Engine: few fixes for dashboard, system groups and namespacing
Engine: Refs #3613 - Enabling a UI controller test for activation keys to
set a baseline for controller test updates.
Merge pull request #3352 from ehelms/engine-spec-controller

Engine: Refs #3613 - Enabling a UI controller test for activation keys t...
Engine: Refs #3615 - Fix repo discovery test