Rewrite Network Details with Angular

Summary
=======
This is a rewrite of the network details page for provided for a single network. The current page has several inline tables showing ports, subnets and DHCP agents. This will be split into a properly tabbed design with modern UI/UX, AngularJS, and the new REST API endpoints. This initial blueprint will achieve absolute feature parity with an improved design.

Motivation
========
Networking is a major feature within Horizon, but it is somewhat limited by the interface currently available. This blueprint aims to make the Network Details into a small scale "network dashboard" for each network, so that most facets of it can be customised from a single location. This rewrite will also pull in the Curvature topology to help visualise an individual network, when it is merged.

Description
=========
- Network details redesigned as a tabbed page with new UI/UX principles and AngularJS
- Load data on initial request, to ensure fluid navigation
- Bring in Curvature topology for single network
- Where possible, reuse and extend generic 'details' CSS
- Where possible, reuse existing directives and other JS from the Launch Instance work

UX
===
This blueprint will include a significant change to the UX of the network details page, but will be building on existing design ideas from the Angular Launch Instance work. Where possible, existing API points and directives will be reused. Designs are based on Invision and community feedback, and will likely evolve as patch sets are released.

Wireframes, Mocks, Videos and UI Markup
---------------------------------------------------------
https://openstack.invisionapp.com/d/main#/projects/2782340

Testing
======
Needs extensive testing via Jasmine. <horizon_url>/jasmine

Outside Dependencies
==================
No changes to external services

Requirements Update Required
========================
- Curvature (new Network Topology): https://blueprints.launchpad.net/horizon/+spec/curvature-network-topology
- Generic Details CSS: https://review.openstack.org/#/c/158881/
- May need to extend Neutron REST API

Doc Impact
=========
N/A