use Koha prox number report

[phette23]

Rather than an API request for each patron to check their prox number, we could run a simple Koha report which lists username and borrower.cardnumber pairs to check if a number has changed. This would greatly speed up the script and reduce the number of HTTP requests, but require an additional manual step since we probably don't want it to be a public JSON report.

[phette23]

I don't think this is worth the extra work and needing to pass another command-line parameter. If the report could be public so it didn't require signing into Koha that might make it worthwhile, but I'm not sure we should expose a username:cardnumber map.