Description of problem:

OSP director RHEL registration templates (tripleo-heat-templates/extraconfig/pre_deploy/rhel-registration/environment-rhel-registration.yaml) don't allow you to specify more than one value for rhel_reg_pool_id. 

The rhel-registration logic also can't be applied on a pre-role basis and needs to be.

To account for the different SKU's required by different nodes in the overcloud there are multiple pool ids required in a deployment. Those id's need to be applied per role so that controller sku's can be matched to a controller, ceph skus to storage and compute sku's to computes.

Without this, all nodes get the ONE pool id, which means they are getting the wrong SKU.

Version-Release number of selected component (if applicable):
openstack-tripleo-heat-templates-6.0.0-12.el7ost

How reproducible:


Steps to Reproduce:
1. Deploy OSP with director 
2. Put a rhel_reg_pool_id into environment-rhel-registration.yaml


Actual results:
rhel_reg_pool_id is assigned to all nodes.

Expected results:
There should be a way to put multiple pools in and assign them per role (or node)

Additional info: