Include additional Formio form metadata in REST responses

[baddlan]

Besides the form schema, some Formio form metadata determine the type of form to render, namely the display property.

Currently the /scenarios/{uuid}/form endpoint in Services and Tasks only returns the schema which is passed in as the Formio renderer's components property as follows:

{
  "id": "pay-taxes",
  "method": "POST",
  "action": "/scenarios/56e3b33e-fc2a-4e61-b1fe-0935aa9e26ed/submissions",
  "type": "formio",
  "schema": [
    { Component 1 ... },
    { Component 2 ... },
    ...
  ]
}

We need to inject the form display property somewhere in there as described in https://github.com/formio/formio.js/wiki/Form-JSON-Schema#form-json