Fix #1188 Add presets for the whole task

[offtherailz]

Importer provides the possibility to update the whole tranform chain updating the "transformChain" entry in the task.

Allowing this in the task, we can configure presets like this to allow correct transforms preset, so it fix #1188:

{
        "state": "READY",
        "data": {
            "format": "GeoTIFF"
        },
        "changes": {
            "task": {
                "transformChain": {
                    "type": "raster",
                "transforms": [{
                     "type": "GdalWarpTransform",
                     "options": [ "-t_srs", "EPSG:4326", "-co", "TILED=YES", "-co", "BLOCKXSIZE=512", "-co", "BLOCKYSIZE=512"]
                 }, {
                     "type": "GdalAddoTransform",
                     "options": [ "-r", "average"],
                     "levels" : [2, 4, 8, 16, 32, 64, 128]
                 }]
             }
            }
        }

    }

[coveralls]

Coverage increased (+0.09%) to 80.887% when pulling c28b1ec on offtherailz:iss1188 into e2ef856 on geosolutions-it:master.