Package fr3_impedance_controller_real in nix env

Including all deps. Tested with nix develop then roslaunch franka_example_controllers ....

Issue with libfranka version, in the end needed to use fetchGithub in Nix to get proper files.

Closes #7 (closed)

fr3_impedance_controller_real/include/franka_example_controllers/cartesian_impedance_example_controller.h

@@ -180,6 +180,7 @@ public:
 
   //* ----- PRINTER --------------------------------------------------------------------------------
   void print_end_effector_states();
+  void print_dynamics();
 };
 
 }  // namespace franka_example_controllers