In addition to adding a new barcode plugin, this commit begins
refactoring the barcode generation code using a new module,
C4::Barcodes::ValueBuilder. From the POD:
This module is intended as a shim to ease the eventual transition
from having all barcode-related code in the value builder plugin
barcode.pl file to using C4::Barcodes. Since the shift will require
a rather significant amount of refactoring, this module will return
value builder-formatted results, at first by merely running the
code that was formerly in the barcodes.pl value builder, but later
by using C4::Barcodes.
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
