LP#1748986 Billing Statement View

LP#1748986 Billing Statement View

Over time, Evergreen has developed a rich set of features to support
various billing scenarios.  Unfortunately, our interface has not kept up
in some ways, and this leads to some confusion at times, particularly
for front line staff.

One way to bring clarity is to apply better grouping, labeling, and
ordering of the various transactional events.  By doing so, we can
generate a billing "statement" with similarities to the statements we
regularly encounter when dealing with other financial institutions.

This branch does so for the staff client view, but it also seems viable
to carry over the same idea to an eventual patron (or print) view as
well.

Signed-off-by: Dan Wells <dbw2@calvin.edu>