Refactor nova.conf docs so they also appear in install guide.

Fixes bug https://bugs.launchpad.net/openstack-manuals/+bug/1043935

Cherry-picked from https://review.openstack.org/17293

This is an old commit that never got backported into folsom.

Change-Id: Ie95008a430c06f9ec5b6c2fd7d6ba5c17862c3d2
Document Trusted Compute Pools

Describe how to configure for using Trusted Compute Pools.

Based on:
 *  http://wiki.openstack.org/TrustedComputingPools
 *  https://lists.launchpad.net/openstack/msg18825.html
 (Email from Dale Stewart)

 See also:
 *  http://wiki.openstack.org/OpenAttestation

 This patch also introduces a new chapter called "Security
 Hardening" into the Compute Admin guide. I expect this chapter
 will eventually include discussions on how to integrate with
 other security-related tech, e.g., SELinux/sVirt.

Cherry-picked from https://review.openstack.org/16783

This is a backport of an older commit that hadn't been merged.

Change-Id: I6f2bfb28496b5d2115dd2d2649f431ae35635891
Merge "Document Trusted Compute Pools" into stable/folsom
Merge "Refactor nova.conf docs so they also appear in install guide." into stable/folsom