Copy and start editors in one of the Devfile containers

[l0rd]

Is your enhancement related to a problem? Please describe

There are 2 different ways to run editors today: as Theia in its own sidecar contaienr or as VS Code that is hosted in one of the Devfile container. As a result Theia and VS Code behaviors are not consistent and are harder to maintain.

VS Code cannot run in its isolated container as its extensions need to run where the dev tools are and cannot run in a remote container.

Describe the solution you'd like

Rather than running their own sidecar, IDEs should be copied in a volume by an initcontainer and executed in one of the containers defined in the Devfile.

• Theia should be adapted to this new behavior (VS Code and JetBrains IDEs are already adapted)
• If there are no container in a Devfile the editor should be executed in the default DevComponent
• If there are more than one container in a Devfile the editor should be executed in the container with attribute controller.devfile.io/component-role: plugin-host if it exist, otherwise in the first container that has mountSources: true.

Additional context

This is a subtask of #21340

[l0rd]

This has been done for JetBrains IDEs as part of #20863. We are not going to do it for Che-Theia, so closing this issue.