Remove ingress.https with unused kube-lego references, rely on ingress.tls and ingress.annotations

[yuvipanda]

kube-lego was the precursor to cert-manager, and has been dead for years and years now

[consideRatio]

Cleanup of ingress.https

ingress.https as a whole is soleley used for ingress.https.type=kube-lego. If we remove type from the schema, it will error as much as if we remove all of ingress.https. Due to this, I've added a commit cleaning it up fully.

Note that mybinder.org-deploy makes use of this configuration. In practice the annotation kubernetes.io/tls-acme is also respected by cert-manager as a signal that it should be active, but it requires some configuration to specify default issuer etc alongside it - see https://cert-manager.io/docs/usage/ingress/.

I think removing this is a fine call, but it requires adjustments to deployments having it explicitly enabled (the default is not).

Config migration

Deployments with ingress.https.enabled=true need to set ingress.annotations and ingress.tls -> .hosts / .secretName going onwards instead I think.

In practice for mybinder.org-deploy, examplifying with the prod config, I think the following changes would need to be made.

1. Let the mybinder chart remove the binderhub.ingress.https section
2. Let the mybinder chart have binderhub.ingress.annotations including kubernetes.io/tls-acme=true
3. Let binderhub.ingress.tls look like binderhub.jupyterhub.ingress.tls configured here, declaring a secret name kubelego-tls-binder-prod to avoid making a change of name.

Like that, I think mybinder.org will render like it did before this change as well.

Config migration example that verified PR

I did some chart rendering and concluded that the before / after config below led to the same content (besides key ordering and indentation).

# possible use before this config
# helm template . --values before-config.yaml --show-only templates/ingress.yaml > before-ingress.yaml
ingress:
  enabled: true
  hosts:
    - example.com
  https:
    enabled: true
    type: kube-lego

# equivalent config after this PR
# helm template . --values after-config.yaml --show-only templates/ingress.yaml > after-ingress.yaml
ingress:
  enabled: true
  hosts:
    - example.com
  annotations:
    kubernetes.io/tls-acme: "true"
  tls:
    - secretName: binderhub-tls-binder-release-name
      hosts:
        - example.com

git diff --no-index -- before-ingress.yaml after-ingress.yaml

[yuvipanda]

Thanks @consideRatio.

I am going to wait to make sure I have access to the curvenote member as well (jupyterhub/mybinder.org-deploy#2920) before merging this and deploying it on mybinder.org