Discovery: restore preference to latest unicast pings describing the same node

Closes #7702
[TEST] added trace logging for index recovery in GeoBoundsTests
[TEST] Additional logging info for node with primary
Aggs enhancement - allow Include/Exclude clauses to use array of terms as alternative to a regex
Closes #6782
Parent/child: If a p/c query is wrapped in a query filter then CustomQueryWrappingFilter must always be used and any filter wrapping the query filter must never be cached.

Closes #7685
Fixed explanation for GaussDecayFunction

The explanation now gives the correct value instead of the negative.
[TEST] Fix test explain now that explanation is fixed