docs/source/usage: link to recipes for full listing

It is not immediately obvious to the new user to look up recipes, so
link to it after the example.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
docs/source/recipes: update available list

Update the list of recipes from recipes/ in the source directory.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>