Add registration/edit time barcode restrictions

Add registration/edit time barcode restrictions

In the quest to not let staff put bad data into the system (losing battle,
but hey, gotta keep trying, right?), add a barcode regex specifically for
patron registration.

This intentionally does *not* check the opac "is this a barcode?" value.

Use cases for not checking that value include, but are not limited to:

Special "barcodes" for staff accounts. Specific OUs may have a barcode
regex of ".*" to ensure they can use anything for these accounts.

Different prefixes per library - To prevent libraries from using another
library's prefix, but still detect all of them as barcodes.

Special case "this is a barcode" checks for the opac, like legacy barcodes
that should no longer be assigned to new patrons, or on edits.

Signed-off-by: Thomas Berezansky <tsbere@mvlc.org>