Add Cisco N1K plugin support in Horizon

This adds Horizon capability to configure and
use network profiles and policy profiles
on the Cisco Nexus 1000V to be used with
networks and instances as is done via neutron
CLI.

To turn on the new dashboard the local_settings
file needs to turn the profile_settings NEUTRON
config variable to cisco.

TODO items include creating a better palate
of unit tests that will run not only when
the cisco n1k subplugin is being used but
in default setting as well.
Need to remove the conditional statements
in the unit tests and make it inclusive.
Additionally need to get a better solution
for how the dashboard/panel registration will
work. Should it be a boolean or check for vendor
specific names.
Also some cleanup and refactoring of commonly
used code everywhere.

Implements: blueprint horizon-cisco-n1k

Change-Id: If6e797ac28c8486cfa92e02742c409d193d9ec84
Merge "Add Cisco N1K plugin support in Horizon"