Some semantic check and exception catching for more robustness

[Cryst4L9527]

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Basic Info

Info	Please fill out this column
Primary OS tested on	Ubuntu20.04
Robotic platform tested on	gazebo simulation of turtlebot3

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Description of the bugs

Hi, I'm researching on testing ROS program and improve the robustness of programs facing possible malformed inputs. There are several improvements can be made for a more robust running.

There are two possible bugs with malformed user input:

First, there is no check for the pub_period, if a negative or zero value is set to the period, there will be a crash throwing the error 'std::invalid_argument' when set the publisher:

  std::chrono::milliseconds period(pub_period_);
  timer_ = create_wall_timer(
    std::chrono::duration_cast<std::chrono::nanoseconds>(period),
    std::bind(&EkfLocalizationComponent::broadcastPose, this));

crash info:

terminate called after throwing an instance of 'std::invalid_argument'
  what():  timer period cannot be negative

Second, there is a possibility that the timestamp of the pose message can be negative because of malfunction or intentional design. And there will be an exception 'std::runtime_error' when set the value to a TimePoint:

auto imu_callback =
    [this](const typename sensor_msgs::msg::Imu::SharedPtr msg) -> void
    {
     ...
     tf2::TimePoint time_point = tf2::TimePoint(
     std::chrono::seconds(msg->header.stamp.sec) +
     std::chrono::nanoseconds(msg->header.stamp.nanosec));
    ...
   }

crash info:

[INFO] [1668342157.570762430] [loc2d_ros]: New laser configured (id=0 frame_id=base_scan)
terminate called after throwing an instance of 'std::runtime_error'
  what():  cannot store a negative time point in rclcpp::Time

Therefore, I add a senmantic check for pub_period as the same as the other params, and catch the exception in the imu_callback. Hope you can accept the PRs.

[rsasaki0109]

Thanks！