[ros] docstring use ros_class variable

Used to create the topic and to generate doc.
While here, add a default_frame_id for some components, the one without
will keep the morse convention, which is the same than the topic name
("/robot/sensor"). Which can also be overriden by an kwargs of name
"frame_id".
[ros] pseudo-wrap mathutils for docgen
[doc] add tool to generate datastream doc