Only actually needed servers should be listed and none is then implied
if no servers are listed.
Outputs a warning if "none" is still set as a server.
Closes#18466
RFC 7686 states that:
> Applications that do not implement the Tor
> protocol SHOULD generate an error upon the use of .onion and
> SHOULD NOT perform a DNS lookup.
Let's do that.
https://www.rfc-editor.org/rfc/rfc7686#section-2
Add test 1471 and 1472 to verify
Fixes#543Closes#10705