Minibroker updates

[btat]

• Explain the usage of various flags/Helm values (E.g. overrideParams) and add best practices for using them
• Table of services for Minibroker is outdated (confirm with PM if we still want this table)
  • RabbitMQ should be added to the list
  • The versions are likely outdated
  • Confirm if the 2 versions of the table are still required. Currently there's one for Kube <= 1.15 and one for Kube >= 1.16