Proxy provider unauthenticated blacklist

[AR2000AR]

Is your feature request related to a problem? Please describe.
I'm trying to protect a app that doesn't support restricting account creation to a list of user (or any other providers). I need to allow all urls except / and /login. Unfortunately golang regexp don't support negative lookahead and the proxy provider only allows whitelisting paths

Describe the solution you'd like
Having an authenticated paths regexp field applied after the unauthenticated one.

Describe alternatives you've considered
Another solution would be to support a regexp lib that can do a negative lookahead.

Additional context
App in questions in a self hosted kutt instance.