Miscellaneous doc additions and xrefs

contents/contents-pre-install
- deleted pre-install/4100-mode-ha -- see HA

install-guide
- 0070-networks info is merged with ref-arch/nova-intro material -- see network
  - 0100-understand* -- pulled two of the xrefs into ref-arch/6050*;
    the reference to a neutron blog doesn't work and is out of place so I
    deleted it.  This file is then deleted.
  - 0150-flatdhcp and 0170-flatdhcp info is included in
    ref-arch/nova-info/0620-nova-flatdhcp and deleted
  - 0190-vlanmanager is included in ref-arch/0630-vlan.rst
  - 0200-fuel-deployment and 0210-config are included in the
    ref-arch/0630-nova file.  Yes, this introduces multiple headers
    into this file but it seems the safest solution at this point.
    When we straighten out the content, we'll fix the structure.
- the entire 0010-* hierarchy is moved to pre-install - see hardware config

planning (pre-installation)
- 0060-quick-install -- file deleted; contents pulled into
  user-guide/2000*; see Happy Path
- 4000-summary-planning updated -- see HA
- 4100-mode-ha  removed -- see HA
- 4400-nodes-roles updated -- see HA
- 4500-hardware.rst -- see hardware
- 0010-prerequisites.rst -- see hardware

ref-arch
- 0014-compact -- see HA
- Modified 6000-network-architecture to call docs in network-concepts
  (6010-logical-networks, 6020-public-floating-ip,
  6030-router, and 6034-switch)
- Moved 6030-router and 6034-switch into network-concepts

terminology
- ha.rst -- see HA
- mongodb.rst -- add that it is just for ceilometer; added xrefs
- mysql.rst -- added xrefs and note  that MongoDB is used for Ceilometer
- neutron -- rewrote information, added links to planning and ref-arch sections.
  Also removed "formerly Quantum" from the title so it is more appropriate
  for links in other docs.

user-guide
- 2000* -- see HA, Happy Path
- Added links to other docs on the roles-and-nodes page

HA
- created terminology/ha.rst with basic info and xrefs to
  to the ref-arch information about ha implementation.
- added link to the install screen for choosing HA
- added link to article from the ref-arch section.
- added link to install screen page to ha-term article
- planning guide: removed section (blank) for choosing HA/non-HA mode
  and added info to roles-nodes about choosing HA replicas; updated
  the summary table appropriately

Hardware planning
- Moved content from install/0010*/0000-hdwr-sizing* to pre-install/\
  4500-hardware.rst; deleted the install file. Also added link to bom
  page.
- The rest of the 0010-prerequisites files are left intact but moved
  to the Planning Guide, positioned as an appendix that is referenced
  from 4500-hardware.

Networking
All material moved from install-guide/0070-network
to nova-network section of ref-arch
- install/0070-networks files merged with ref-arch/nova-intro files

Happy Path docs (install, deploy, configure)
This is all in the User Guide now just because this was the easiest
way to get all the steps in the right order.  Once that is done, we
can split it if we want to although I actually kind of like having it
in one place.
- Divided guide into four sections: Download/install, boot fuel, create
  environment, configure environment.  Plus other stuff at the end that
  is untouched in this CM.
- Broke up the summary table so an appropriate portion is in each of the
  main sections.
- Had to create a couple other sub-sub sections under Create to accomodate
  new structure.
- Moved information about downloading and installing Fuel from pre-install
  and install guides.
- Added lots of xrefs to other portions of the docs with supporting info.
- Deleted the grub screens that were duplicates

Change-Id: Ie833fcafb8a96b5919cece20d838969e2633834a
(cherry picked from commit a43e47c7e3866439ae660b7b9f2a4f9ef65ffb8a)