CORE-4914 Added query to count filtered items in folder.

Added count-filtered-items-in-folder to the queries map.
Added an icat/number-of-filtered-items-in-folder function.
CORE-4914 Update number-of-items-in-folder to return total.

Updated the count-items-in-folder in the queries map to select the count as "total".
Updated icat/number-of-items-in-folder to return this result map instead of just the number value, similar to the return value of the new icat/number-of-filtered-items-in-folder function.
Simplified the SELECT statements in the count-items-in-folder query.