In entries explanations and configuration, make it possible to "split"
the list in multiple sub-lists visually: a ``null`` item should just
create an empty space, not display a list item "dot"
* move chart of accounts higher in document
* rewrite text a bit
* split controls to left-hand column
* remove dependencies between operations
* highlight result of last-applied operation (not very good looking atm)
* convert listickles to React widget
* add interactive hooks to introduction/definition paragraphs
* add highlighting to various items based on (2)
todo: ragged bottom edge using a SVG border-image?
