Add gRPC Transport support (#356)

Co-authored-by: JimhHan <50871214+JimhHan@users.noreply.github.com>

infra/conf/grpc.go

@@ -0,0 +1,16 @@
+package conf
+
+import (
+	"github.com/golang/protobuf/proto"
+
+	"github.com/xtls/xray-core/transport/internet/grpc"
+)
+
+type GRPCConfig struct {
+	ServiceName string `json:"serviceName"`
+	MultiMode   bool   `json:"multiMode"`
+}
+
+func (g GRPCConfig) Build() (proto.Message, error) {
+	return &grpc.Config{ServiceName: g.ServiceName, MultiMode: g.MultiMode}, nil
+}