GEOMESA-281 Create a strategy decider function

refactored to create a Decider that decides on Strategy (attribute index, spatiotemporal index or id index)
Strategy executes the query
this will be the framework upon which more complicated cost analysis of query planning is based
The reason for splitting Decider out is because you can make these strategy decisions without needing all of the other parameters required to create an instance of IndexQueryPlanner. This facilitates testing at least. Would it help if we put the Decider in the same file, but at the bottom?