Problem: A website for Indigo needs to be built from its current
tutorial, however the tree structure is not ideal, in particular:
- markdown files for the chapters are organized alonside the source
  code for the examples
- the example modules are tied to the documentation structure
These constitute a problem because we want the documentation's file
tree structure to be independent from the examples and vice-versa.

Solution: move the markdown files in a flat new directory and move
the example modules in a topic-based tree structure.