replace std streams with ROS logging

[christianrauch]

Describe the bug
Parts of the code base is using std streams, such as std::cerr, instead of the ROS logging. This makes it difficult to control and redirect the output within the ROS logging system.

To Reproduce
See

control_toolbox/control_toolbox/src/sinusoid.cpp

Lines 59 to 63 in e0b6957

	void Sinusoid::debug()
	{
	std::cout << "offset=" << offset_ << " amplitude=" << amplitude_ << " phase=" << phase_
	<< " frequency=" << frequency_ << std::endl;
	}

,

control_toolbox/control_toolbox/src/pid.cpp

Line 141 in e0b6957

std::cerr << e.what() << '\n';

, and

control_toolbox/control_toolbox/src/pid.cpp

Line 151 in e0b6957

std::cerr << "PID: Invalid gains: " << error_msg << ". Skipping new gains." << std::endl;

for example.

Expected behavior
These and other occurances should use the ROS logging intrastructure.

Screenshots
If applicable, add screenshots to help explain your problem.

Environment (please complete the following information):

• OS: [e.g. Ubuntu]
• Version [e.g. Humble]
• Anything that may be unusual about your environment

Additional context
Add any other context about the problem here, especially include any modifications to ros2_control that relate to this issue.

[github-actions]

This issue is being labeled as stale because it has been open 45 days with no activity. It will be automatically closed after another 45 days without follow-ups.

[christophfroehlich]

The linked classes do not have any ROS dependency and therefore we can't just use rclcpp logging. Instead of writing to output streams we could either return a string or throw an exception to be catched from the calling ROS wrapper.