update and use rs/dnscache implementation instead of custom (#13348)

additionally optimize for IP only setups, avoid doing
unnecessary lookups if the Dial addr is an IP.

allow support for multiple listeners on same socket,
this is mainly meant for future purposes.

cmd/gateway-main.go

@@ -154,8 +154,6 @@ func ValidateGatewayArguments(serverAddr, endpointAddr string) error {
 
 // StartGateway - handler for 'minio gateway <name>'.
 func StartGateway(ctx *cli.Context, gw Gateway) {
-	defer globalDNSCache.Stop()
-
 	signal.Notify(globalOSSignalCh, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT)
 
 	go handleSignals()
@@ -268,7 +266,7 @@ func StartGateway(ctx *cli.Context, gw Gateway) {
 		return GlobalContext
 	}
 	go func() {
-		globalHTTPServerErrorCh <- httpServer.Start()
+		globalHTTPServerErrorCh <- httpServer.Start(GlobalContext)
 	}()
 
 	globalObjLayerMutex.Lock()