GEOMESA-6, GEOMESA-198 Secondary Indexing

* Table layout consists of a catalog table to store metadata and three tables
  per simple feature type (spatiotemporal index, attribute index, record table)
* Queries consisting of only isEqualTo and LIKE with trailing wildcard are satisfied
  by the attribute index (an inverted text index)
* Backward compatibility is maintined with Old-style 0.10.x spatiotemporal index tables
  containing embedded simple feature type metadata
* The number of shards is now configurable per simple feature type
* SpatioTemporal Index, Attribute Index, and Record Tables are all presplit
* Bug fixed in imports in FeatureEncoder
* Implementing AttributeIndexFilteringIterator as a subclass of Filter