Document how to install Eclipse Che on major k8s providers

[tolusha]

Is your task related to a problem? Please describe

We don't have any docs describing how to install Eclipse Che on k8s cluster [1], but instead we have a lot of requests like this [2].

[1] https://eclipse.dev/che/docs/stable/administration-guide/installing-che/
[2] Eclipse che on Plain Kubernetes - Is it possible if so, detailed steps required. Minikube is NOT idel #21743
[3] Document how to setup an OIDC provider #21304

Describe the solution you'd like

In general, we have to know a couple of things before deploying Eclipse Che on k8s cluster:

• kubernetes public domain
• OIDC provider url
• client id
• client secret

1. Prepare patch file

cat >>cr-patch.yaml <<EOF
apiVersion: org.eclipse.che/v2
spec:
  networking:
    domain: <DOMAIN>
    auth:
      identityProviderURL: <IDENTITY_PROVIDER_URL>
      oAuthClientName: <CLIENT_ID>
      oAuthSecret: <CLIENT_SECRET>
EOF

2. Run command to deploy Eclipse Che

chectl server:deploy --platform k8s --che-operator-cr-patch-yaml cr-patch.yaml --skip-oidc-provider-check

The main problem is in configuring OIDC provider and users would like to have a clear doc how to do this. I found a couple of successful user's stories while going through similar issues [1] [2] [3] [4] [5]. The main idea is to translate those stories in the article for che-docs

• https://eclipse.dev/che/docs/stable/administration-guide/installing-che-on-microsoft-azure/ (AKS)
• Devworkspace native auth on Kubernetes - Unauthorized! Configured service account doesn't have access #21049 (comment) (Rancher)
• Devworkspace native auth on Kubernetes - Unauthorized! Configured service account doesn't have access #21049 (comment) (GKE)
• https://github.com/flavienbwk/eclipse-che-kubernetes (Kubeadm)
• https://eclipse.dev/che/docs/next/administration-guide/installing-che-on-amazon-elastic-kubernetes-service/ (EKS)
• MicroK8S OIDC Issue #21378 (comment) 404 preview URL of the Eclipse Che Port extension #22445 (microk8s)

Describe alternatives you've considered

No response

Additional context

• EKS - Installation guide on EKS #23209 / Deploy Che on EKS. #22615

[l0rd]

Another related issue #21304