Create a "Guides" section in the docs

[infomiho]

Right now, we have a collection of different useful (and specific) gists that we keep track of in the learning materials repo: https://github.com/wasp-lang/learning-materials?tab=readme-ov-file

We'd like to include links to those gists in our docs somehow. Since they are quite specific, concrete examples, it makes sense to maybe include them in a "Guides" section that contains recipe styles information.