Add support for ephemeral volumes

[amisevsk]

What does this PR do?

Adds support for volume components with ephemeral: true, which are provisioned as emptyDir volumes in the workspace pod.

This PR updates the logic for determining whether a container needs storage. The new logic is:

• If any non-ephemeral volumes are defined, we need storage
• If any container component has mountSources: true, we need storage unless there's an explicit projects volume with ephemeral: true
  this new check does not check that any container has mountSources as before, since that is covered by the first case, or an error (a container mounting a volume that is not defined)

I had to update the relevant test to support this change, and also added tests to cover the ephemeral volume use cases.

I've also added a sample that showcases some of the ways to use ephemeral volumes:

• We can override the default projects volume to be ephemeral
• We can override volumes in plugins to be ephemeral (we make the theia plugins volume ephemeral)

What issues does this PR fix or reference?

Closes devfile/api#310

Is it tested? How?

1. Deploy controller, make sure CRDs are updated to include support for ephemeral volumes (I made that mistake...) (see: Update devfile/api dependency and message with info about failures #270)
2. Deploy plugin templates (make install_plugin_templates)
   • Note some of the templates have been updated to e.g. use an ephemeral volume for remote runtime
3. Deploy sample that uses emptyDir

   kubectl apply -f samples/with-k8s-ref/emptyDir-theia.yaml

4. Verify:
   • All volumes in workspace pod are emptyDir (`kubectl get po -o yaml | yq -y '.spec.volumes')
   • All volumeMounts in containers refer to these emptyDir containers
   • No finalizer is set on the workspace
   • The workspace runs normally

I had a strange issue testing locally that I'm currently blaming minikube for: when I initially apply the sample, the volumes in the devworkspace are simply

      - name: projects
        volume: {}

but applying twice correctly shows the ephemeral field. No idea why that's happening and praying it doesn't reproduce elsewhere.

[amisevsk]

@sleshchenko I might be seeing your issue from #269 (review) -- using che-theia:next I'm stuck at the loading spinner, but switching to 7.26.0 I have no issues.

[sleshchenko]

Tested and the described scenario works as expected, apart from fact that I needed to patch theia to be 7.26.0 which is know issue.

[amisevsk]

/test v5-devworkspaces-operator-e2e

[JPinkney]

Tested and working as expected 👍

[amisevsk]

From Serhii:

DevWorkspace with

spec:
  started: true
  template:
    components:
    - name: theia-next
      plugin:
        kubernetes:
          name: theia-next
          namespace: devworkspace-plugins
    - name: machine-exec
      plugin:
        kubernetes:
          name: machine-exec
          namespace: devworkspace-plugins

has PVC mounted but no finalizer set; looking into it.

[amisevsk]

/test v5-devworkspaces-operator-e2e

[sleshchenko]

Still LGTM, additional thanks for handling the reported bug.

[openshift-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: amisevsk, JPinkney, sleshchenko

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