Web: document JS plugins

[literat]

WHEN (situation): as a user,
WHAT: I want better documented JS plugins,
WHY: because I need to know how they are used.

Acceptance criteria
each JS plugin has its documentation as part of the component where it is used
Implementation notes (optional)
edit readme
link from twig to web
They are freely available externally. It would be nice to have them documented. So that others know when and how to use them, maybe they have a usecase for them. Right now, it's always just the components that say, use this one and that's it.
We need to figure out how to document it, document it and get it into Supernova.