Baseline setup is in place. End-to-end interaction with the K8s API is
g2g.

- Pipelines VAW endpoint is in place and performing static validation as
  well as dynamic validation of changes to guard against accidental data
  loss.
- Implemented VAW endpoints for Streams & Tokens.

A few updates to the Pipeline controller to ensure it better handles
changes to the pipeline spec.

closes #52

- Cleaning up old secrets after their frontend Token CRs have been
  removed.
- Cleaning up old services after their backend STS or STS pods/replica
  counts have been removed.
- Re-creating frontend Services for Stream STS & STS pods when needed.
- Scheduler is now creating frontend Services for Stream STS as part of
  the StatefulSetUpdated handler. This is where Ingress creation will go
  in the future as well. Also deleting the STS if the Stream doesn't
  exist.
- Cleaning up old services when an STS is deleted.