switch all other services to struct tag based env config

proxy/pkg/cs3/client.go

@@ -10,7 +10,7 @@ import (
 func newConn(endpoint string) (*grpc.ClientConn, error) {
 	conn, err := grpc.Dial(
 		endpoint,
-		grpc.WithInsecure(),
+		grpc.WithInsecure(), //TODO: depreciated
 		grpc.WithUnaryInterceptor(
 			otelgrpc.UnaryClientInterceptor(
 				otelgrpc.WithTracerProvider(
@@ -28,6 +28,7 @@ func newConn(endpoint string) (*grpc.ClientConn, error) {
 
 // GetGatewayServiceClient returns a new cs3 gateway client
 func GetGatewayServiceClient(endpoint string) (gateway.GatewayAPIClient, error) {
+	// TODO: check connection pooling
 	conn, err := newConn(endpoint)
 	if err != nil {
 		return nil, err