GEOMESA-146 WPS import process for performance

@elahrvivaz sounds like a good idea. I'll add a check. @jnh5y I think that we should totally write a new general ingest process. There is already one in geoserver called gs:Import but unfortunately it takes an input feature collection with n features and creates n size-1 feature collections and then calls addFeatures() n times. For us this caused big issues because we read/write the bounds on addFeatures per collection. 

At some point I'll contribute a patch to geoserver maybe to suggest the change to geoserver's import.