Adapt WorkspaceLoader to workspaces created with Devfile

[sleshchenko]

Description

There is added an ability to create a workspace with Devfile instead of WorkspaceConfig, and in such case, WorkspaceLoader is not able to start a workspace because it expects WorkspaceConfig be present in workspace.
It is needed to rework WorkspaceLoader to use Devfile from workspace if WorkspaceConfig is absent.

Reproduction Steps

1. Create a workspace with Devfile via swagger ${CHE_HOST}/swagger/#!/workspace/createFromDevfile.

Devfile JSON

{
  "specVersion": "0.0.1",
  "name": "with-devfile",
  "projects": [
    {
      "name": "nodejs-mongo-app",
      "source": {
        "type": "git",
        "location": "https://github.com/ijason/NodeJS-Sample-App.git"
      }
    }
  ],
  "components": [
    {
      "name": "theia-editor",
      "type": "cheEditor",
      "id": "org.eclipse.che.editor.theia:1.0.0"
    },
    {
      "name": "exec-plugin",
      "type": "chePlugin",
      "id": "che-machine-exec-plugin:0.0.1"
    },
    {
      "name": "mongodb",
      "type": "dockerimage",
      "image": "mongo",
      "endpoints": [
        {
          "name": "mongo",
          "port": 27017,
          "attributes": {
            "public": "false",
            "discoverable": "true"
          }
        }
      ],
      "mountSources": false,
      "volumes": [
        {
          "name": "mongo-storage",
          "containerPath": "/data/db"
        }
      ],
      "memoryLimit": "250Mi"
    },
    {
      "name": "nodejs-app",
      "type": "openshift",
      "reference": "node-js.yaml",
      "referenceContent": "apiVersion: v1\nkind: List\nitems:\n-\n  apiVersion: apps/v1\n  kind: Deployment\n  metadata:\n    name: web\n    labels:\n      app: nodejs\n  spec:\n    replicas: 2\n    selector:\n      name: web\n    template:\n      metadata:\n        labels:\n          app: nodejs\n        name: web-controller\n      spec:\n        containers:\n        - image: node:0.10.40\n          command: ['tail', '-f', '/dev/null']\n          args: []\n          name: web\n          ports:\n          - containerPort: 3000\n            name: http-server\n          volumeMounts:\n           - mountPath: /projects\n             name: projects\n        volumes:\n         - name: projects\n           persistentVolumeClaim:\n             claimName: projects\n- apiVersion: v1\n  kind: PersistentVolumeClaim\n  metadata:\n    name: projects\n  spec:\n    accessModes:\n     - ReadWriteOnce\n    resources:\n      requests:\n        storage: 2Gi\n-\n  apiVersion: v1\n  kind: Service\n  metadata:\n    name: web\n    labels:\n      name: web\n  spec:\n    type: LoadBalancer\n    ports:\n      - name: web\n        port: 80\n        targetPort: 3000\n        protocol: TCP\n    selector:\n      app: nodejs\n- apiVersion: v1\n  kind: Route\n  metadata:\n    name: che\n  spec:\n    to:\n      kind: Service\n      name: web\n    port:\n      targetPort: web\n"
    }
  ],
  "commands": [
    {
      "name": "run",
      "actions": [
        {
          "type": "exec",
          "component": "nodejs-app",
          "command": "cd ${CHE_PROJECTS_ROOT}/nodejs-mongo-app/EmployeeDB/ && npm install && node app.js"
        }
      ]
    }
  ]
}

2. Try to start a workspace by opening `$CHE_HOST`/che/with-devfile

[akurinnoy]

@sleshchenko, opening ${CHE_HOST}/che/with-devfile in browser calls gwt-ide loader. I looked into it and didn't find such code which tries to grab a workspace configuration or to start a workspace. The loader expects for a workspace to be in the running state. I only found and fixed a smal bug for loader not to get machines in case of stopped workspace.

I close this issue in favor of this one #13293.