Provide more structure and overview

[acka47]

I see two things that can help to make it easier to navigate in a longer lesson like https://metafacture.github.io/metafacture-tutorial/02_Introduction_into_Metafacture-Flux.html.

1. Add more headings
2. Add some boxes to highlight things, for example:

Note

• We played around with the Metafacture Playground.
• We learned that a Metafacture Flux workflow is a combination of modules with an inital text string or an variable.
• We got to know different modules like open-http, as-lines. decode-json, encode-yaml, print

Tip

More modules can be found in the documentation of available flux commands.

We might also consider using the library carpentry setup that e.g. has boxes for "overview" and "key points", see e.g. https://librarycarpentry.github.io/lc-git/aio.html