Differential Rate Limiting Based on White Lists

[plantimals]

I am operating nostream at nostr.drss.io. I would like to put specific pubkeys on a whitelist to grant them a different rate limit than the default for the relay. I don't want there to be no limit at all, just a different one. I have a personal use case for this, that of publishing events pulled from RSS feeds. I created this issue at @Cameri's request in note19kw9a07dw2qdpxwm23m022vfed2acfaclejsexwpaev5a2lp0k7sluh76w.

[etemiz]

This can be useful also for IPs in a relay sync use case.