Adding AWS support to openshift-ansible module

- Update documentation to say that ssh configuration need to point to the private key file
- Removing the -p argument when calling time .... because it is misintrepreted by ruby
- Turning the cluster.sh to agnostic in its help/error message by replacing explicit reference to GCE by a a variable
- Fixing a bug within the playbooks that incorrectly references the minions and master fact group. Needs a better fix with a call to AWSHelper.generate_env_host_type_tag_name()
- Adding playbooks for AWS, which are almost of copy/paste for those of GCE: Needs a refactor to reduce code duplication
did you test this change in GCE?

This was working in GCE, so I don't think it should change.

Also, note that AWS and GCE treat tags differently. In AWS you can optionally set a value for a tag. When you set a value, the value is what's after the _.

So, this is a scary change to make, please ensure it's needed for GCE.

@jwhonce could you work with Akram on this, again, we do NOT want to break GCE, as that's what @maxamillion  and co are using right now.