BZ# 1128282 - Remove descendant hostgroups from the foreman host form

Users should not assign hosts directly to the deployment hostgroups.
This removes those choices from the host edit form.
Extend the foreman API to disallow setting the hostgroup via the API
Also remove hostgroups from multiple selected hosts modal
Do not allow the regular hosts controller to accept deployment hg
Cinder changes to support create volume types in quickstack

Add the cinder_create_volume_types param and default to true
Change the cinder backend type strings to shorter strings (without
_backend)
simple subnets
Custom repositories configuration
Simple Subnets UI
Simple Subnets validations
Simple Subnets: fix network_address validation
Merge pull request #337 from ares/custom_repo

Custom repositories configuration
Simple Subnets: UI fixes

- Makes the "New Subnet" button green
- Adds inline help for "Network Address"
- Sets "External DHCP" as the default value for dhpc_server
Merge pull request #338 from ares/simple_subnets_backend

Simple subnets backend
Simple Subnets: update the network_configuration page

Append the newly created subnet to the list of subnets.
Merge pull request #339 from ifarkas/simple_subnet-auto_refresh

Simple Subnets: update the network_configuration page
Add support for n1kv core plugin

Adds the ability to select the N1KV plugin. Configuration of the plugin
is done in both the selection screen and advanced configuration screen.
Merge pull request #331 from bcrochet/new-cinder-names

Cinder changes to support create volume types in quickstack
Explictly set type for hash params
Refactor Equalogic and Cisco Nexus to use extracted IP validator
Merge pull request #340 from bcrochet/n1kv

Add support for n1kv core plugin