multi-root workspaces should be default when using Dev Workspaces / devfile v2

[benoitf]

Is your task related to a problem? Please describe.

multi-root is currently optional in Eclipse Che and will soon be a default.
But for DevWorkspaces it should be enabled now by default

Describe the solution you'd like

Do not need to specify attribute in devfile for devfilev2 to enable multi-root. It should be the only choice available.

Describe alternatives you've considered

N/A

Additional context

N/A

[azatsarynnyy]

@RomanNikitenko below are some useful notes for this issue ⬇️

To detect if we're running a DevWorkspace, check the DEVWORKSPACE_NAME environment variable, e.g. process.env['DEVWORKSPACE_NAME'].

To start a workspace with the DevWorkspace engine

1. Start your local cluster, e.g. minikube start --memory 8192 --disk-size 50g --driver virtualbox
2. Start Che with the dev-workspace engine: chectl server:deploy --platform=minikube --workspace-engine=dev-workspace
3. grab https://raw.githubusercontent.com/devfile/devworkspace-operator/main/samples/flattened_theia-next.yaml and save it a local file on you machine.
4. Start a DevWorkspace:

kubectl create ns my-dev-workspace
kubectl apply -f flattened_theia-next.yaml -n my-dev-workspace
kubectl get dw --all-namespaces

The latest command should print you a Che-Theia URL to follow.
Note, it requires some time to start a workspace. So, if there's no URL - just wait several seconds and repeat the last command.