feat/106 elk certs

[joshgamache]

Addresses #106. Adds TLS certificates for inter-pod communication in the ELK stack.

Changes 🚧

• Manually generated and added an internal Certificate Authority (per Elastic documents).
  • Added readme directions to reproduce.
  • Added generation of certificates from CA on pod launch.
• Connected certificates to Elastic and Kibana pods.
• Refactored some config into config maps

Notes 📝

• The process to add the Kibana (internal) certificate is currently manual, as Kibana doesn't contain the same tools as Elastic containers did to generate certificates.
• The route for Kibana is currently not reachable, as with security enabled it needs an externally signed certificate to be useful. You can still reach the pod with oc port-forward.

With approval of this and #100, we should deploy the stack to be available to ingest log data. Kibana is still accessible, albeit with a few more steps, so we can still review logs as needed.

[pbastia]

Nice! This looks sound to me