Local dns recursor and dns over https

[kpcyrd]

I'm currently running a dns recursor locally for two reasons:

• I don't want to send all my dns lookups to the network provided dns recursor
• I still need to send some dns lookups to the network provided dns recursors for non-public zones

I would also like to switch to encrypted dns with dns-over-https (or dns-over-tls), but it seems this would currently require running two recursors, one for custom rules and one for dns-over-https.

We could integrate this into snail and make the decision where a request should go either using a config or a script (so we can also make the decision based on SSIDs), while also supporting dns-over-https.

Integrating this into snail would also help avoiding issues that could be introduced by #11.

[kpcyrd]

A prototype is currently available in the dns branch. Merging is blocked since I currently use the git master of trust-dns.