tf2_tools.view_frames and tf2_ros.tf2_monitor - allow configurable topics

Feature request

Feature description

In ArduPilot, we namespace all our topics, including TF, so they can be remapped at launch time. We want to run the view_frames tool on the frames published by ArduPilot, but we can't unless we remap them. In a large system, it's nice to be able to run diagnostics without changing the behavior of the system.

Implementation considerations

Add the following options

• tf_static_topic which defaults to the exist tf_static
• tf_topic which defaults to the existing tf

Example usage:
ros2 run tf2_tools view_frames --tf_static_topic=/ap/tf_static --tf_topic=/ap/tf