Replace kubernetes-dashboard by headlamp since its retired

[mborne]

Context

See https://github.com/kubernetes-retired/dashboard :

This project is now archived and no longer maintained due to lack of active maintainers and contributors.
...
Please consider using Headlamp instead. It was recently moved under the sig-ui.

Actions

• Look for the docs and existing helm chart
• Try a first deployment (done on branch 86-headlamp)
• Experiment OIDC login (I FAIL)

Resources

• https://github.com/kubernetes-sigs/headlamp#readme
• https://headlamp.dev/docs/latest/installation/in-cluster/ : in-cluster install with helm

# first add our custom repo to your local helm repositories
helm repo add headlamp https://kubernetes-sigs.github.io/headlamp/

# now you should be able to install headlamp via helm
helm install my-headlamp headlamp/headlamp --namespace kube-system

• https://headlamp.dev/docs/latest/installation/in-cluster/dex/ (good news, no more need to deploy oauth2-proxy!)

config:
  oidc:
    clientID: "<YOUR-CLIENT-ID>"
    clientSecret: "<YOUR-CLIENT-SECRET>"
    issuerURL: "<YOUR-DEX-URL>"
    scopes: "email"