Make it easy to spin up CI jobs in own GKE cluster

In some cases, it can be handy to create a standalone GKE cluster for a particular job. This could be for a few reasons:

• To truly recreate Production, it may be necessary to isolate the environment from other running applications.
• Support new clusters in specific regions, to run deploy and run CI in specific locations world wide

This could be beneficial for Prometheus and monitoring for a few reasons:

1. When running load tests, it will be nice to be able to stand up a separate cluster on different hardware, since we will be potentially stressing these systems out fairly completely. This would avoid concerns around impacting other environments like Production.
2. By supporting different regions, we could run the browser/load tests from various worldwide regions. This could be beneficial for a few reasons. For a company with a worldwide distributed application. we'd be able to hit the local copies. For the latency and smoke tests, we'd be able to generate this traffic from different parts of the globe, testing latency and reachability.
3. For more traditional cases, environments review apps could also be stood up in their own cluster for isolation.