Add a bevy dependency graph to the contributor book (that stays up to date)

[ItsDoot]

Using https://github.com/jplatte/cargo-depgraph, we can have the main bevy repo run a CI task on main whenever a new PR is merged that updates the dependency graph and stores it somewhere, then we simply link this standard location as an image in the contributor book.

This would help give a visual of the higher to lower level APIs and crates that bevy provides.