feat: Support multiple hostnames in ingress definitions

[frankjkelly]

Motivation

• Kubernetes Ingress definitions allow multiple DNS hostnames - see https://kubernetes.io/docs/concepts/services-networking/ingress/#name-based-virtual-hosting for examples

Modifications

• Because the number of changes was significant with a high likelihood of breaking backwards compatibility I decided to add a new ingress definition template file and the choice as to which to use is based on whether the user uses the old
  .hostname definition or the new .hosts (array of objects)

Verifying this change

• Make sure that the change passes the CI checks.

NOTE: Testing locally in Minikube using settings such as

      ingress:
        enabled: true
        tls:
          enabled: true
        hosts:
        - host: one.saas-dev.cogitocorp.us
          excludePaths: []
          includePaths: []
          tls:
            enabled: true
            secretName: secret-one
        - host: two.saas-dev.cogitocorp.us
          excludePaths: []
          includePaths: []
          tls:
            enabled: true
            secretName: secret-two

Creates the following

kubectl get ingress
NAME                    CLASS    HOSTS                                                   ADDRESS   PORTS     AGE
pulsar-dashboard        <none>   one.saas-dev.cogitocorp.us,two.saas-dev.cogitocorp.us             80, 443   4m
pulsar-proxy            <none>   one.saas-dev.cogitocorp.us,two.saas-dev.cogitocorp.us             80, 443   4m
pulsar-pulsar-manager   <none>   one.saas-dev.cogitocorp.us,two.saas-dev.cogitocorp.us             80, 443   4m

and also

kubectl get ingress pulsar-proxy -o yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    meta.helm.sh/release-name: pulsar
    meta.helm.sh/release-namespace: cogito
  creationTimestamp: "2023-11-21T15:20:29Z"
  generation: 1
  labels:
    app: pulsar
    app.kubernetes.io/managed-by: Helm
    chart: pulsar-3.1.1
    cluster: pulsar
    component: proxy
    heritage: Helm
    release: pulsar
  name: pulsar-proxy
  namespace: cogito
  resourceVersion: "801"
  uid: 0a3ef2c4-4653-4cfa-bd70-58adce1fdf72
spec:
  rules:
  - host: one.saas-dev.cogitocorp.us
    http:
      paths:
      - backend:
          service:
            name: pulsar-proxy
            port:
              number: 443
        path: /
        pathType: ImplementationSpecific
  - host: two.saas-dev.cogitocorp.us
    http:
      paths:
      - backend:
          service:
            name: pulsar-proxy
            port:
              number: 443
        path: /
        pathType: ImplementationSpecific
  tls:
  - hosts:
    - one.saas-dev.cogitocorp.us
    secretName: secret-one
  - hosts:
    - two.saas-dev.cogitocorp.us
    secretName: secret-two
status:
  loadBalancer: {}