Install Prometheus on e2e cluster

[dtfranz]

As part of e2e cluster setup, install prometheus to gather metrics from operator-controller and catalogd when using the test-e2e-metrics makefile target.

When e2e tests are run through our makefile targets, there are a number of setup jobs that run to create the runtime environment for e2e, including: kind-cluster, kind-load, kind-deploy, etc. Once operator-controller and catalogd have been installed on the kind cluster, a makefile target should be run to install prometheus. To keep this overhead separate from the normal maintainer testing workflow of running test-e2e/e2e targets, this environment should only be included when running the test-e2e-metrics target.