Support for multiple "dns-link" entries with different prefixes

[martinheidegger]

Right now dnslink does not allow to use both dnslink=/ipfs/... and dnslink=/other-protocol/ at the same time, because it limits the amount of entries to 1:

https://github.com/JChanceHud/dnslink/blob/cf5cd4cdb468b581ccdb3460fae6d9b6ee80ea8b/cmds/resolve.js#L35-L45

This makes it impossible for other look-ups to also use the dnslink system. It would be good to allow "prefixes" (or to return more than one entry) if more than one entry is given (in order to be able to choose the desired protocol one.