Provide visualization of modules in documentation

[gavinr]

Tinkering around with rollup-plugin-visualizer, it's pretty easy to embed this into our rollup build, and Jacob and I were noticing how useful it is to get a sense of the overall project structure and layout:

We were thinking about if it might be useful to set this up as a build output and have it embedded in the documentation (README or wiki) to help new contributors understand esri-leaflet more easily? Looking for comments/thoughts. Thanks!

[jwasilgeo]

https://next.github.com/projects/repo-visualization

If we want to semi-automate it: https://next.github.com/projects/repo-visualization#integrate-into-your-own-projects

Direct link to play around now: https://octo-repo-visualization.vercel.app/?repo=esri%2Fesri-leaflet (and be sure to exclude the spec/ path for a bit more fun 😉)