Port `dataUrl` and `dataUrlType`

[na9da]

These config options are available in master. eg config:

 {
          "id": "405ab2d2",
          "name": "State Suburbs",
          "description": "State Suburbs",
          "type": "mvt",
          "url": "https://vector-tiles.terria.io/SSC_2016_AUST/{z}/{x}/{y}.pbf",
          "dataCustodian": "[Australian Bureau of Statistics](http://www.abs.gov.au/)",
          "info": [
            {
              "name": "Licence",
              "content": "[Creative Commons Attribution 2.5 Australia (CC BY 2.5 AU)](http://creativecommons.org/licenses/by/2.5/au/)"
            }
          ],
          "layer": "SSC_2016_AUST",
          "lineColor": "#FF0000",
          "fillColor": "#DDDDFF",
          "rectangle": [
            96.81694,
            -43.7405,
            159.10921,
            -9.14217
          ],
          "keepOnTop": true,
          "nameProperty": "SSC_NAME16"
        }

[wibily]

check that this affects "about this data" when data is not available in v8 for broken data sets. related to download links for the raw data