Combination of expensive and whitelisted relay

Requires users to manually register themselves to be able to publish events and pay a fee except whitelisted pubkeys

https://github.com/1440000bytes/relayer/tree/master/examples/expensive-whitelist

Cc: nostr:npub180cvv07tjdrrgpa0j7j7tmnyl2yr6yr7l8j4s3evf6u64th6gkwsyjh6w6