No StatusChangeLogger for ROS2

[b-adkins]

The BT::StatusChangeLogger is a handy class that automatically logs changes in the active behavior node's state as the tree is run. BehaviorTree.CPP comes with loggers for stdout, a file, a database, etc.

I could not find an equivalent such logger for ROS2. Is there any reason the ROS2 repo shouldn't have one?

I wrote one.