GEOMESA-482 fixing geoserver namespace issues

* Implementing namespace aware methods in AccumuloDataStore, FeatureStore, FeatureSource
* Allowing complex namespaces in SimpleFeatureTypes
GEOMESA-483 Created SFT Builder

Users can create SFT spec strings programatically
Allows setting default DTG and TableSplitter
GEOMESA-418 Time-enabled layer previews are not handled optimally

* Recognizing binary inequality filters involving canonical time variable as temporal filters and handling them like before/after.
* allowing before/after and inequality operators to take named field on left or right of operator
* test verifies that < and <= are treated like BEFORE; > and >= are treated like AFTER
* moved filter typeclasses to utils module and implemented ops
* warn-logging errors on STIdxStrategy.execute rather than letting geotools eat them
* modifying temporalFilters to properly capture temporal filters with the temporal attribute on the right
GEOMESA-485 Geometries are being written to the attribute index

Filter out geometry descriptors from getSecondaryIndexedAttributes