Update docs/ structure

To set a base for upcoming docs changes, the docs directory structure
has been streamlined to follow a simplified version of Django's docs.

The old _draft folder has been removed. Both files from there and the
current docs that don't fit nicely into the new structure are in _old/
for the moment.
Docs: Explain docs/ directory structure
Manual merge branch 'feature/betterdocs'

Conflicts:
	docs/source/recipes.rst