GEOMESA-488, 492 Understand and remove use of jai_core, CoverageReader's VersioningIterator's random name string isn't created properly

Excluded jai_core and removed usages of jai_core functionality from geomesa-plugin. Also
fixed an issue with a random name not being properly generated for VersioningIterator
in CoverageReader
do these get included in the plugin jar now? can you verify that it won't affect the dependency tree at all? if so, we'll have IP issues...