Proxy URL systems break our search

[frizensami]

E.g., NUS Proxy changes dl.acm.org to https://dl-acm-org.libproxy1.nus.edu.sg/

[frizensami]

All known proxies are at: https://libproxy-db.org/

This is called "url rewriting" through software like EZProxy. Specifically, institutions use "proxy by hostname" nowdays.

[frizensami]

Addressed in #155