GEOMESA-133 SimpleFeature UserData lost in IndexQueryPlanner

Add functions to transfer the SimpleFeatureType UserData into and out of IteratorSettings, which would otherwise be lost when passed to the Iterators via DataUtilities.encodeType
Hmm... as a tiny performance nitpick, I'd suggest replacing map with foreach and calling sft.getUserData.put(key, value) directly so that no additional map is created.