Use a dedicated server as webview domain

[azatsarynnyy]

Signed-off-by: Artem Zatsarynnyi azatsary@redhat.com

What does this PR do?

Uses a dedicated endpoint to deploy all webviews separately from Che Theia editor endpoint.
It increases security since all webviews don't have access to the data of Che Theia window.

Note, this PR depends on a couple of other PRs (already merged):

• plugin unique endpoint feature introduced by the PR Ingress/Route per plugin endpoint che#15432
• PR Add Che Theia editor endpoint to expose the plugins' webviews on a different origin to make them isolated from Che Theia origin che-plugin-registry#335 that enables additional endpoint for the webviews

To test it:

• run Che with enabled TLS and using self-signed certificates. For the details, see the comments Test self-signed certificates for Che on Kubernetes/OS deployed with chectl (helm/operator installers) che#14035 (comment) and Test self-signed certificates for Che on Kubernetes/OS deployed with chectl (helm/operator installers) che#14035 (comment). Use Che Server from the image quay.io/lkrejci/che-server:7.7.0-issue-15283 which includes unique endpoint feature
• run a workspace from the following Devfile:

metadata:
  name: webviews
apiVersion: 1.0.0
components:
  - reference: https://raw.githubusercontent.com/azatsarynnyy/che-plugin-registry/master/v3/plugins/eclipse/che-theia/next/meta.yaml
    type: cheEditor

• see that theia sidecar has webviews endpoint which is used for loading webview of Welcome page

What issues does this PR fix or reference?

closes eclipse-che/che#15616

Release Notes

Docs PR

[vzhukovs]

Other looks good to me

[che-bot]

✅ E2E Happy path tests succeed 🎉

See Details

• Jenkins job

• logs and configs

• Happy path tests DevFile

• images:

name	link
che-theia	docker.io/maxura/che-theia:591
che-theia-endpoint-runtime-binary	docker.io/maxura/che-theia-endpoint-runtime-binary:591

Tested with Eclipse Che Single User on K8S (minikube v1.1.1)