Port package to ROS 2

[clalancette]

@vmayoral I did a few more fixups in a611d8a . In particular:

• I removed the rest of the Eigen compat stuff, since now we have Eigen3 REQUIRED, we won't ever run into those situations
• I removed the stuff bumping the version and the CHANGELOG. While appreciated, this will be done automagically by catkin_generate_changelog/catkin_prepare_release when we prepare the next release of this package. Also, we'll most likely bump the major or minor number for this package when releasing into ROS 2, to ensure there can never be version conflicts between ROS 1 and ROS 2.

With that, I'm happy with this, and I'm going to merge. Thanks for the contribution!

[vmayoral]

Thanks a lot for the fixes @clalancette! Happy to contribute.