Make subdomain matching optional - especially YouTube!#211

Blocking some websites require this to retain usability of Opal. Example:
Blocking YouTube doesn’t work correctly because the accounts.youtube.com subdomain handles google account authentication. The following url gets blocked in the authentication flow:

https://accounts.youtube.com/accounts/SetSID?ssdc=1&sidt=xxxx&continue=xxx&tcc=1&dbus=XX

This is pretty inconvenient. The same applies for some Facebook subdomains. I’m sure there are other examples too.

This should be a pretty low-hanging fruit, I’m a backend software engineer. Could we pleaaase make this happen? I’ll be happy to open a pull request if there’s an open-source community edition or something on github.