Generate barcodes and push them into LDAP

Generate barcodes and push them into LDAP

Add a custom API to open-ils.actor for generating barcodes; accepts one
argument, user ID, which gets the barcode set to their new value. If no
arg is passed, just generates a new barcode and returns it (should be
useful on the patron editor screen).

As far as pushing the barcodes into LDAP goes, I can't confirm that the
updates are actually working, because I can't see them, but the lack of
errors suggests that it's working.

Signed-off-by: Dan Scott <dscott@laurentian.ca>