Support devfile v2 factory link

[l0rd]

Is your enhancement related to a problem? Please describe.

If a github repository has a devfile.yaml that uses v2 of the devfile spec we are not able to start the workspace.

Describe the solution you'd like

Support factory link that points to a git repo of petclinic with a devfile 2.0 that has just maven and mysql components (no che-theia plugins). Theia and machine exec are implicitly added by Che. Subtasks:

• Update che-server endpoint that returns devfiles from the GitHub URL to support Devfile 2.0 platform team
  • Analyse if we need to add 2.0 Java model support in che-server -> no
  • Validate the devfile 2.0 syntax (not the content) -> not working now, We need to update justify lib To make devfile v2 validation work, update justify library #18901 then it should be as simple as put the schema in Devfile v2 validation on /factory/resolve #18948
• Transform a Devfile 2.0 in a DevWorkspace CR controller and platform team
  • Review how the che server could return the default namespace of a user (resolve che-<placeholder>) platform team
  • Create the user namespaces where the CR should be created (if it doesn't exist yet) controller team
  • Specify the routing class when starting a Che workspace controller team
• Add the default ~~ /implicit ~~ (are not supported for milestone 1) Che components to the DevWorkspace CR (theia and machine exec)
  • [che-server] Provide default editor and plugins on REST API platform team [che-server] Provide default editor and plugins on REST API #18986
• Improvements to devfile v2 factory flow support Improvements to devfile v2 factory flow support #19147
  • Namespace should be created if it does not exist
  • Specify the routing class che
  • Default editors and plugins should be propagated to the DevWorkspace CR namespace, we should not rely on the DevWorkspaceTemplate registry

Bugs:

• DevWorkspaces with Che routing is not started due: ExposedEndpoint.Attributes should handle free-form JSON as values ExposedEndpoint.Attributes should handle free-form JSON as values devfile/devworkspace-operator#302

[sleshchenko]

It's implemented in someway, there are still some points which needs to be addressed on Dashboard side, and they can be tracked in #19147

[l0rd]

I have actually reopened this epic and made it clear that #19147 is a subtask of it. I am doing it because in the milestone we only track issues at the epic level.

[sleshchenko]

The last PR is merged on dashboard side, the main workflow should work.