Starts install guide chapter for neutron, cleanups

This begins the install guide chapter for neutron,
and cleans up some sections from the guide that will
not be used even as references.

* hypervisor_selection - not relevant for the adventure
where the choice is done prior, and makes some difficult
value judgement statemtnts

* scripted ubuntu install - not the purpose of this guide
and old content that isn't helpful for the rewrite

* image-troubleshooting - empty section, belongs in
cloud-admin-guide anyway

* vnc-console - already in image_install

* identity_config_keystone - already better done in
individual sections

* install nova-volume - very dated content, already
in cinder install

* basic install files - no longer needed for reference

Change-Id: I1979eeba091c7118db7cc30ad7c66f30345fe49d
Merge "Starts install guide chapter for neutron, cleanups"