[AMORO-3966][Helm] Support custom volumes and volumeMounts

[AbhishekPathania]

What changes were proposed in this pull request?

Adds support for custom volumes and volumeMounts in Amoro Helm chart, enabling users to mount additional volumes without modifying chart templates.

Resolves #3966

Why are the changes needed?

Users need to mount custom resources like:

• Java truststore for SSL/TLS certificates
• Configuration files
• Secrets (API keys, credentials)
• Persistent volumes

Currently, these require forking/patching the chart.

Does this PR introduce any user-facing change?

Yes. Users can now specify custom volumes in values.yaml:

volumes:
  - name: java-truststore
    secret:
      secretName: java-truststore-secret

volumeMounts:
  - name: java-truststore
    mountPath: /opt/java/truststore
    readOnly: true

How was this patch tested?

• Verified Helm template rendering with custom volumes
• Tested with Java truststore secret mount
• Confirmed backward compatibility (no volumes specified = no change)

[xxubai]

+1. Thanks @AbhishekPathania