Support Neutron Network Sharing (via RBAC)

Summary
=======
Support the Neutron Network RBAC feature in Horizon.

Details here:
https://docs.openstack.org/ocata/networking-guide/config-rbac.html

Related to:
https://blueprints.launchpad.net/horizon/+spec/network-bandwidth-limiting-qos

Motivation
========
Network RBAC is a hugely useful feature that allows sharing of networks between projects, as such the dashboard should expose this functionality, especially since it has been present in Neutron since Liberty.

Description
=========
The exact implementation details still need to be worked out.

On network list we need to show the RBAC rules in some fashion, and possibly show more information in a tab on the network detail page. A workflow to share a network to another project will need to be added. The target project field should by default be a drop down of the projects you have access to, but also allow targeting a specific project if the ID is known.

QoS RBAC may also need to be included.

An alternative may be to create a new panel specifically for Neutron RBAC policies, but that may be much worse UX.

UX
===
Needs discussion based on possible implementation options.

Wireframes, Mocks, Videos and UI Markup
---------------------------------------------------------
n/a

Testing
======
No plans yet.

Outside Dependencies
==================
This is already a Neutron API that Horizon would use.

Requirements Update Required
========================
n/a

Doc Impact
=========
n/a