GEOMESA-508 Factoring Out Common Code from STIdxStrategy and QueryPlanner

* Factored out four duplicated functions from STIdxStrategy and QueryPlanner into a trait.
GEOMESA-495,GEOMESA-524 Remove further use of jai_core, Fix bug of using wrong column names in export transformation

GEOMESA-495:
Excluded jai_core from gt-coverage and gt-process-feature. Added jai_core as a provided dependency incompute,core, jobs, plugin, and tools.

GEOMESA-524:
Fix bug of using wrong column names in export transformation
GEOMESA-481 Remove use of decodeKey in STII and II.
GEOMESA-413 fixing transform of index iterator
GEOMESA-515 Factor out WrappedSTFilter

* Moved WrappedSTFilter out of iterators into IteratorHelpers trait
GEOMESA-526 Fix Spark RDD and Avro Encoders