Separate dependencies on Gazebo to a component?

[peci1]

This could have been a pretty nice general-use library. However, the dependency on Gazebo makes it really hardly usable for some non-relevant applications. What about separating-out the gazebo-dependent parts into a component, so that the main component only depends on ign-common or so? Edifice+?

[chapulina]

I think that's a good idea 👍