fix(core): add constructors for grp config, state and robot config

Author: juelg

python/rcs/_core/common.pyi

@@ -105,10 +105,10 @@ class Gripper:
     def shut(self) -> None: ...
 
 class GripperConfig:
-    pass
+    def __init__(self) -> None: ...
 
 class GripperState:
-    pass
+    def __init__(self) -> None: ...
 
 class Hand:
     def __init__(self) -> None: ...
@@ -276,7 +276,7 @@ class RobotPlatform:
     def value(self) -> int: ...
 
 class RobotState:
-    pass
+    def __init__(self) -> None: ...
 
 class RobotType:
     """

src/pybind/rcs.cpp

@@ -372,9 +372,9 @@ PYBIND11_MODULE(_core, m) {
       .def_readwrite("tcp_offset", &rcs::sim::SimRobotConfig::tcp_offset)
       .def_readwrite("robot_platform",
                      &rcs::common::RobotConfig::robot_platform);
-  py::class_<rcs::common::RobotState>(common, "RobotState");
-  py::class_<rcs::common::GripperConfig>(common, "GripperConfig");
-  py::class_<rcs::common::GripperState>(common, "GripperState");
+  py::class_<rcs::common::RobotState>(common, "RobotState").def(py::init<>());
+  py::class_<rcs::common::GripperConfig>(common, "GripperConfig").def(py::init<>());
+  py::class_<rcs::common::GripperState>(common, "GripperState").def(py::init<>());
   py::enum_<rcs::common::GraspType>(common, "GraspType")
       .value("POWER_GRASP", rcs::common::GraspType::POWER_GRASP)
       .value("PRECISION_GRASP", rcs::common::GraspType::PRECISION_GRASP)