Custom best-hold selection sort order

Custom best-hold selection sort order

The ranking algorithm that chooses the best hold to target a copy in
hand at a capture time used to be fairly simple.  It had two modes, FIFO
and not-FIFO, and that was it.

This change allows full configuration of that algorithm.  In other
words, when the system captures a copy and sets out to evaluate what
hold, if any, that copy might best fulfull, site staff of sufficient
permission level are now empowered to choose exactly which comparisons
the systems makes in what order.  This gives said staff much greater
flexibililty than they have today over holds policy.

For more information, see the included tech spec documents.

Signed-off-by: Lebbeous Fogle-Weekley <lebbeous@esilibrary.com>
Conflicts:
	Open-ILS/src/sql/Pg/002.schema.config.sql
	Open-ILS/src/sql/Pg/950.data.seed-values.sql

Signed-off-by: Mike Rylander <mrylander@gmail.com>