Gazebo on Gentoo

Ok, so there is an update here…

Apparently, Gazebo 8 will not be ready for Lunar. So I suppose we should just keep things where they are currently.

Moreover, I am starting my internship at OSRF on Monday (May 22nd) and talking with @tfoote about working on a better solution to using ROS on Gentoo than the ROS overlay approach I am doing currently.

The idea is to generate ebuilds from the ROS buildfarm for all bloom-released packages.