GEOMESA-446 Wire up TDI via WPS

The only issue I know of is that the TDI process must be ran with xml as the output type currently. json does not work. Currently, we embed the json timeseries inside of the xml output (unless there is a query hint specifying to return an encoded time series object rather than the timeseries in json form).
This DateTimeFormat object is constant; move it outside the loop, and even outside the method to avoid creating it repeatedly.  Place it just above the method where it's used so it's clear what code it's associated with.