Setup SSH Keys for the nova users on compute hosts

This is required for live migrations and resizes to work
* Creates the nova .ssh directory
* Sets up SSH private and public Keys
* Adds public key to authorized_keys file
* Sets StrictHostChecking=no for the nova user

Fixes #5
Fixes #6
fixes issue #8
Merge pull request #7 from andymcc/nova_key_fix

Setup SSH Keys for the nova users on compute hosts
Merge pull request #10 from cloudnull/Issue8

fixes issue #8
aggregating all package installation types

This will ensure that all packages set from a common place and
that all python packages are wheels being installed from our
repo.

Pip is now setup with a pip config which is part of the users
$HOME folder within the .pip directory.  All indexing is disabled
by default and links to pip wheel are provided on a per project/commit
bases.

Setup SSH Keys for the nova users on compute hosts
This is required for live migrations and resizes to work. All nova-compute
hosts will have their own ssh keys and all other nodes will have the public
keys. This way there are no shared keys between nodes.
Process:
  * Creates the nova .ssh directory
  * Sets up SSH private and public Keys
  * Adds public key to authorized_keys file
  * Sets StrictHostChecking=no for the nova user

Two new plays were create to allow for the keys to be rotated at anytime and
to add nova-compute nodes to the environment.