commander: add failsafe state machine with webassembly simulation

to run the simulation:
install sdk: https://emscripten.org/docs/getting_started/downloads.html
make run_failsafe_web_server
open http://0.0.0.0:8000/

Co-authored-by: Konrad <konrad@auterion.com>

msg/vehicle_status_flags.msg

@@ -1,5 +1,8 @@
 # TODO: rename to failsafe_flags (will be input to failsafe state machine)
 #
+# Input flags for the failsafe state machine.
+# Flags must be named such that false == no failure (e.g. _invalid, _unhealthy, _lost)
+# The flag comments are used as label for the failsafe state machine simulation
 
 uint64 timestamp				# time since system start (microseconds)
 
@@ -19,22 +22,26 @@ uint32 mode_req_other             # other requirements, not covered above (for e
 
 bool calibration_enabled
 bool pre_flight_checks_pass		# true if all checks necessary to arm pass
-bool auto_mission_available
-bool angular_velocity_valid
-bool attitude_valid
-bool local_altitude_valid
-bool local_position_valid		# set to true by the commander app if the quality of the local position estimate is good enough to use for navigation
+bool auto_mission_available		# Mission available
+bool angular_velocity_valid 		# Angular velocity valid
+bool attitude_valid 			# Attitude valid
+bool local_altitude_valid               # Local altitude valid
+bool local_position_valid		# Local position estimate valid
 bool local_position_valid_relaxed	# Local position with reduced accuracy requirements (e.g. flying with optical flow)
 bool local_velocity_valid		# set to true by the commander app if the quality of the local horizontal velocity data is good enough to use for navigation
-bool global_position_valid		# set to true by the commander app if the quality of the global position estimate is good enough to use for navigation
+bool global_position_valid		# Global position estimate valid
 bool gps_position_valid
-bool home_position_valid		# indicates a valid home position (a valid home position is not always a valid launch)
+bool home_position_valid		# Home position valid
 
-bool offboard_control_signal_lost
+bool offboard_control_signal_lost # Offboard signal lost
+bool geofence_violated 				# Geofence violated
 
 bool rc_signal_found_once
+bool rc_signal_lost # RC signal lost
+bool data_link_lost # Data link lost
+bool mission_failure # Mission failure
 bool rc_calibration_in_progress
-bool vtol_transition_failure                        # Set to true if vtol transition failed
+bool vtol_transition_failure                        # VTOL transition failed
 
 bool battery_low_remaining_time
 bool battery_unhealthy