Rewrite docs

[luizmb]

Simplify chapters, illustrate more with code and pictures, test examples, split some chapters into new markdown files.

[luizmb]

Text must be reviewed, add better animations, move the details to be only on the api documentation (github pages), better examples and tutorial.

[luizmb]

Now the docs are completely outdated. Since it was written, too many things have changed, like the new reactive wrappers, Combine support, side-effects middleware being replaced by PipelineMiddleware, BindableStore and more.