Add compute/storage node roles to compressed_ha

The scenario mappings for compressed_ha include everything necessary
for setting up a functioning 3-node HA cluster. However, it is
conceivable that once a 3-node HA cluster is established, users may want
to increase their compute/storage capacity by adding additional
compute/storage nodes. To make this easier, this patch provides additional
mappings in data/scenarios/compressed_ha.yaml.

Closes-Bug: #1270944
Merge pull request #40 from CiscoSystems/bugs/1270944

Add compute/storage node roles to compressed_ha