Support extraContainers for Goldilocks Dashboard Deployment

[Pyodin]

Hello!
It would be useful if the chart supported adding extraContainers to the dashboard deployment, and extraPorts for the service.

Use case: running an oauth2-proxy sidecar in front of the Goldilocks dashboard in order to expose it securely through an ingress.

Something similar to:

dashboard:
  extraContainers:
    - name: oauth2-proxy
      image: quay.io/oauth2-proxy/oauth2-proxy:<version>
      args:
        - --http-address=0.0.0.0:8081
        - --upstream=http://127.0.0.1:80
        - --provider=<provider>
        - --client-id=<client-id>
        - --oidc-issuer-url=<issuer-url>
        - --redirect-url=<redirect-url>

  service:
    extraPorts:
      - name: oauth-proxy
        port: 8081
        targetPort: 8081

  ingress:
    enabled: true
    ingressClassName: nginx
    rules:
      - host: my-public-domain
        paths:
          - path: /
            pathType: ImplementationSpecific
            servicePort: 8081

Would you be open to supporting something similar to extraContainers and extraPorts for the dashboard deployment/service?
If so, I would be happy to develop this feature :)