Include plain Kubernetes deployment test as part of staging jobs

[gctucker]

Following the outcome of #270, this is about supporting Kubernetes as a standard deployment option in addition to docker-compose. We may end up with a variant of this for the kernelci.org production deployment with Atlas and some form of object storage, but having the option to deploy the API & Pipeline entirely in a plain Kubernetes cluster is useful for other use-cases. In particular, this would make it possible for users to easily create their own Cloud instance.

In order to ensure that Kubernetes deployment works, we should add it to the automated staging jobs as some kind of end-to-end test. We'll then have to decide what to run in docker-compose and what to run in Kubernetes. At first we can continue running actual jobs only via the docker-compose setup as it's probably easier to debug and configure on the staging VM and only do a smoke test with a Kubernetes deployment to check the deployment works.

• Initial automated deployment for API & Pipeline in Kubernetes implemented
• Hook added to the periodic staging job to deploy it from scratch every time
• Basic smoke test added to run in the Kubernetes deployment (e.g. running some kci commands and tests)