Include prometheus deployment in destroy pipeline.
Include prometheus deployment in destroy pipeline.

We want to destroy the prometheus deployment as well as CF when tearing
down a deployment, otherwise it's not possible to fully tear it down
(the terraform-destroy will fail because resources are in use).

alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf