vehicle_command_ack: rename result_param1 to progress and comment usage

To avoid confusion:
- naming consistent with MAVLink definition
- comments about the few different ways the field is used

msg/VehicleCommandAck.msg

@@ -25,7 +25,7 @@ uint8 ORB_QUEUE_LENGTH = 4
 
 uint32 command						# Command that is being acknowledged
 uint8 result						# Command result
-uint8 result_param1					# Also used as progress[%], it can be set with the reason why the command was denied, or the progress percentage when result is MAV_RESULT_IN_PROGRESS
+uint8 progress					# Also used as progress[%], it can be set with the reason why the command was denied, or the progress percentage when result is MAV_RESULT_IN_PROGRESS
 int32 result_param2					# Additional parameter of the result, example: which parameter of MAV_CMD_NAV_WAYPOINT caused it to be denied.
 uint8 target_system
 uint16 target_component 				# Target component / mode executor

src/modules/commander/Arming/ArmAuthorization/ArmAuthorization.cpp

@@ -251,7 +251,7 @@ void arm_auth_update(hrt_abstime now, bool param_update)
 
 		case vehicle_command_ack_s::VEHICLE_CMD_RESULT_DENIED:
 		default:
-			switch (command_ack.result_param1) {
+			switch (command_ack.progress) { // It's not used as progress but as protocol parameter for arm authorization
 			case vehicle_command_ack_s::ARM_AUTH_DENIED_REASON_NONE:
 				/* Authorizer will send reason to ground station */
 				break;

src/modules/mavlink/mavlink_main.cpp

@@ -2604,7 +2604,7 @@ void Mavlink::handleAndGetCurrentCommandAck()
 					mavlink_command_ack_t msg{};
 					msg.result = command_ack.result;
 					msg.command = command_ack.command;
-					msg.progress = command_ack.result_param1;
+					msg.progress = command_ack.progress;
 					msg.result_param2 = command_ack.result_param2;
 					msg.target_system = command_ack.target_system;
 					msg.target_component = command_ack.target_component;

src/modules/mavlink/mavlink_receiver.cpp

@@ -127,7 +127,7 @@ MavlinkReceiver::acknowledge(uint8_t sysid, uint8_t compid, uint16_t command, ui
 	command_ack.result = result;
 	command_ack.target_system = sysid;
 	command_ack.target_component = compid;
-	command_ack.result_param1 = progress;
+	command_ack.progress = progress;
 
 	_cmd_ack_pub.publish(command_ack);
 }
@@ -771,7 +771,7 @@ MavlinkReceiver::handle_message_command_ack(mavlink_message_t *msg)
 	command_ack.command = ack.command;
 	command_ack.result = ack.result;
 	command_ack.from_external = true;
-	command_ack.result_param1 = ack.progress;
+	command_ack.progress = ack.progress;
 	command_ack.target_system = ack.target_system;
 	command_ack.target_component = ack.target_component;
 

src/modules/navigator/navigator_main.cpp

@@ -1418,7 +1418,7 @@ void Navigator::publish_vehicle_command_ack(const vehicle_command_s &cmd, uint8_
 	command_ack.from_external = false;
 
 	command_ack.result = result;
-	command_ack.result_param1 = 0;
+	command_ack.progress = 0;
 	command_ack.result_param2 = 0;
 
 	_vehicle_cmd_ack_pub.publish(command_ack);

src/modules/payload_deliverer/payload_deliverer.cpp

@@ -255,7 +255,7 @@ bool PayloadDeliverer::send_gripper_vehicle_command_ack(const hrt_abstime now, c
 	switch (command_result) {
 	case vehicle_command_ack_s::VEHICLE_CMD_RESULT_IN_PROGRESS:
 		// Fill in the progress percentage field for IN_PROGRESS ack message
-		vcmd_ack.result_param1 = UINT8_MAX;
+		vcmd_ack.progress = UINT8_MAX; // unkown progress according to MAVLink definition
 		break;
 	}