Delete unused Kubernetes/Helm configuration

[chosak]

This commit deletes all existing documentation and configuration around deploying cf.gov using Kubernetes and Helm. This configuration is currently unused and will be replaced in future with an alternate implementation (that will likely recreate some of these pieces).

Checklist

• PR has an informative and human-readable title
• Changes are limited to a single goal (no scope creep)
• Code follows the standards laid out in the CFPB development guidelines
• Project documentation has been updated, potentially one or more of:
  • This repo’s docs (edit the files in the /docs folder) – for basic, close-to-the-code docs on working with this repo
  • CFGOV/platform wiki on GHE – for internal CFPB developer guidance
  • CFPB/hubcap wiki on GHE – for internal CFPB design and content guidance