feat: add queryStrategy option for DNS

app/dns/config.proto

@@ -36,6 +36,12 @@ enum DomainMatchingType {
   Regex = 3;
 }
 
+enum QueryStrategy {
+  USE_IP = 0;
+  USE_IP4 = 1;
+  USE_IP6 = 2;
+}
+
 message Config {
   // Nameservers used by this DNS. Only traditional UDP servers are support at
   // the moment. A special value 'localhost' as a domain address can be set to
@@ -73,5 +79,7 @@ message Config {
   reserved 7;
 
   // DisableCache Disable DNS cache
-   bool disableCache = 8;
+  bool disableCache = 8;
+
+  QueryStrategy query_strategy = 9;
 }