Add order and grouping to response entity type

[loickho]

Returns grouping and fields for given entity. Introduce order and children.

Example:

{
      name: "personalData"
      order: 100
      isRepeatable: false
      children: [
           {
              "name": "firstName",
              "type": "string",
              "required": true,
              "linkage": true,
              "minLength": 1,
              "maxLength": 100,
              "order": 0
          },
      ]
 }