Set timestamp with vehicle commands

The vehicle_command uORB messages had the timestamp unset at 0.

src/drivers/camera_trigger/camera_trigger.cpp

@@ -484,6 +484,7 @@ void
 CameraTrigger::test()
 {
 	struct vehicle_command_s cmd = {};
+	cmd.timestamp = hrt_absolute_time();
 	cmd.command = vehicle_command_s::VEHICLE_CMD_DO_DIGICAM_CONTROL;
 	cmd.param5 = 1.0f;
 

src/drivers/px4io/px4io.cpp

@@ -821,6 +821,7 @@ PX4IO::init()
 		cmd.param5 = 0;
 		cmd.param6 = 0;
 		cmd.param7 = 0;
+		cmd.timestamp = hrt_absolute_time();
 		cmd.command = vehicle_command_s::VEHICLE_CMD_COMPONENT_ARM_DISARM;
 
 		/* ask to confirm command */

src/drivers/vmount/output_mavlink.cpp

@@ -63,6 +63,7 @@ int OutputMavlink::update(const ControlData *control_data)
 		vehicle_command.command = vehicle_command_s::VEHICLE_CMD_DO_MOUNT_CONFIGURE;
 		vehicle_command.target_system = _config.mavlink_sys_id;
 		vehicle_command.target_component = _config.mavlink_comp_id;
+		vehicle_command.timestamp = hrt_absolute_time();
 
 		if (control_data->type == ControlData::Type::Neutral) {
 			vehicle_command.param1 = vehicle_command_s::VEHICLE_MOUNT_MODE_NEUTRAL;
@@ -90,6 +91,7 @@ int OutputMavlink::update(const ControlData *control_data)
 	hrt_abstime t = hrt_absolute_time();
 	_calculate_output_angles(t);
 
+	vehicle_command.timestamp = t;
 	vehicle_command.command = vehicle_command_s::VEHICLE_CMD_DO_MOUNT_CONTROL;
 	vehicle_command.target_system = _config.mavlink_sys_id;
 	vehicle_command.target_component = _config.mavlink_comp_id;