Clarified installation of Networking on dedicated controller node

I clarified various portions of the section for installing Networking
on a dedicated controller node. This patch covers all of the issues
provided in the associated bug. In light of freezing Havana and moving
focus to Icehouse with more significant changes, this patch also
contains several more ambitious clarifications:

1) Reorder various steps to improve flow and consistency with
configuration of other services. For example, other services generally
configure access to the MySQL database fairly early in the section.

2) Combine similar steps. For example, configuring Networking to use
Keystone involves editing neutron.conf and api-paste.ini. Rather than
using two separate steps which may change location and ordering with
future patches, I combined them into one step with substeps for each
file.

3) For the steps affected by this bug, I changed project names to
service names as provided in the conventions section of the
documentation guide.

Change-Id: I04eee95711e3a25e06641602f37b801a659b9e35
Closes-Bug: #1264170
Merge "Clarified installation of Networking on dedicated controller node"