WireGuard outbound: Add remoteDNS & honor TTL (#6620)

Closes https://github.com/XTLS/Xray-core/pull/6569#issuecomment-5263789755

Fixes https://github.com/XTLS/Xray-core/issues/6567#issuecomment-5150957597

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Co-authored-by: LagPixelLOL <2282688304@qq.com>

proxy/wireguard/config.proto

@@ -34,4 +34,5 @@ message DeviceConfig {
   DomainStrategy domain_strategy = 7;
   bool is_client = 8;
   bool no_kernel_tun = 9;
+  repeated string DNS = 10;
 }