LP#1841089 Apply button in Patron Bill History screen in a confusing location

LP#1841089 Apply button in Patron Bill History screen in a confusing location

It's possible to miss the apply button for the date range in bill history
because it's located before the datepickers. The interface also allows
invalid date ranges.

This removes the apply button and watches the start and finish dates. If it's
not first init and they are valid date objects in a valid date range, the
grid refreshes with the new date range query. If start > finish they are set
equal to each other to force a valid range.

Signed-off-by: Dan Briem <dbriem@wlsmail.org>