Administrator password injection

Describe how to configure Compute to support admin password injection.

Closes-bug: #1254563

Backport: havana grizzly

Backport notes:

- The dashboard configuration is landing in Icehouse, it's not in
grizzly <https://review.openstack.org/56151>.

- The Libvirt configuration option is called libvirt_inject_password
in grizzly. In havana, it's "inject_password" in the [libvirt] group.

Change-Id: I63e51ad7bf45387cb79d85e937a805b3804df41a
OVS agent config should apply to ML2 plugin too.

Add a note for mentioning this.

Change-Id: Ic9e625ceff47d49693d6499c098272498595866e
www/.htaccess bad match

updating the training-manuals section by adding the trailing slash for
the source and target. should fix the subdir match error with the trailing slash
gets matched and doesnt get included on the redirect target.

Change-Id: Ia366f50e6b5e7e8890ff0ba0b66eb19029c06263
Closes-Bug: #1255773
Fix Typo Under Virtual Box Introduction

Fixed Typo for Controller Node under Introduction to
Virtual Box Section.

Fixed typo inside image under Host-Only Networking Section.

Closes-Bug: #1245126

implements bp/training-manuals

Change-Id: I129170b3dc69097ec71bf3c9cff6b76e23609b66
Rename metering to Telemetry in Security guide.

Change-Id: I585cb3d2eec31c8fa501e883cd9f3a25e6c4ba34
Merge "OVS agent config should apply to ML2 plugin too."
Merge "Fix Typo Under Virtual Box Introduction"
Merge "Rename metering to Telemetry in Security guide."
Merge "www/.htaccess bad match"
Merge "Administrator password injection"