[Suggestion] Add "queryStrategy" to NameServer

[changyp6]

Hello developers.
Currently, DNS's "queryStrategy" is a global settings for all NameServers.
All NameServers in DNS config can only query 1 type IP address.
If "queryStrategy" is set per NameServer, it will make NameServer more flexible.

For example, some website are faster in IPv4 address, users can only query IPv4 using specific NameServer.

If possible, support setting tag to each NameServer.