Handle the runCommand factory's action in Theia

[ashumilova]

Factory has the ability to set the list of commands, that could be executed inside IDE on particular event and the task is to add support of commands to Theia IDE as well.

Sample:

"actions": [
        {
          "properties": {
            "name": "test"
          },
          "id": "runCommand"
        },
        {
          "properties": {
            "name": "displayIP"
          },
          "id": "runCommand"
        }
      ]

Note: Commands (in GWT IDE) are Tasks (in Theia IDE). So in Theia should use task mechanism for handing runCommand action.