The goal of this component is abstracting away
the difference between metadata fields which are
strings and the ones which are arrays of strings.

This removes the <br> tags which were
previously inserted after every five elements.
Line breaks should be handled dynamically
by the browser.

This makes displaying metadata of an exercise
less verbose. Styling is a bit lacking as of now.

Restructure metadata translations of lists
to make declarations more concise.

Exercises should not depend on search,
so they get their own module.

This is done as to reduce the file size
and complexity of the exercise-details component.

zweimal (and some Test improvments)

Prior to this change, the image would
become full-width on narrow screens,
which looks awful.

Let the mailto link actually include
the email address instead of consisting
only of "mailto:"