K8s Helm Chart - Allow custom secret names and optionally disable cdm creation

[babris]

Hello,

in my use case of the Helm chart, I need to have two separate releases active in the same Kubernetes namespace, each with different configuration values to account for an outlying client application that connects to a different origin cluster.

Currently, this isn't possible, since the expected secret name is hard-coded as zdmproxy and zdmproxy-scb.

In my ideal form of the chart, users would be able to alter the name of the secret such that different releases can be supplied with different configuration values. Additionally, giving users an option to disable creation of the cdm pod as well as the SCB volume mount would help accommodate non-Astra DB target clusters.

This PR adds four fields to the helm values to achieve this:

• secretNameOverride: Overrides the expected secret name, "zdmproxy" by default
• secretScbNameOverride: Overrides the expected SCB secret name, "zdmproxy-scb" by default
• cdm.enabled: Determines whether a cdm deployment is created ("true" by default)
• scb.enabled: Determines whether a SCB volume mount is created from secret zdmproxy-scb ("true" by default)
  • If disabled, then "target_origin_points" will be expected in the "zdmproxy" secret

The defaults exist such that if users do not supply any of the above values, the original functionality is preserved.

With this PR, I hope to welcome a discussion on the above topics as well as any change suggestions.
Thank you for your review.