Member function naming in system_interface.cpp

[AndyZe]

These member functions defy the Google style guidelines and the ROS C++ style guidelines. Was that intentional or should we change them?

hardware_interface/system_interface.hpp

For example, export_state_interfaces() should be exportStateInterfaces() per ROS1 style

Google style guide: https://google.github.io/styleguide/cppguide.html#General_Naming_Rules
ROS1 style guide: http://wiki.ros.org/CppStyleGuide#Function_.2F_Methods

I'm happy to make a cleanup PR if needed

[AndyZe]

It looks like this is pretty widespread throughout the codebase

[gavanderhoorn]

ROS 2 C++ code style allows snake_case.

From Code style and language versions - C++ - Style: Function and Method Naming:

[AndyZe]

Cool. Maintainers, feel free to close the issue