Chart that relates the conceptual designs of RMF with the current packages (#198)

Posted by @orensbruli:

As a newcomer to RMF, I’m trying to go from the chart on this section to the implementation in rmf (and sub) repositories.
Somehow I would like to create a representation of what packages implement what parts of that chart

My first attempt to group the packages is in this PR [doc] Architecture diagram by orensbruli · Pull Request #194 · open-rmf/rmf · GitHub and can be seen here: README.md#architecture

Can we discuss this? Any ideas on a better way to represent it or how to group packages?