The vendor was renamed from `wrm` to `werkraummedia`.
And the namespace vendor was renamed from `Wrm` to `WerkraumMedia`.
That way all references to PHP classes as well as the package name
itself need to be adjusted.
A new PSR-14 event is added that allows to modify the categories to be
assigned to an event.
The event itself (including already existing categories) as well as the
list of categories to be used after import are available.
It is possible to change the categories to be assigned, e.g. keep some
of the existing categories.
That way it is possible for installations to add custom categories to
events.
Relates: #10623
Extbase will properly use mm sorting.
But categories can't be sorted within the TCA tree component.
Therefore it makes more sense to use actual sys_category sorting.
In order to do so, we add our own model and pass the sorting.
That way PHP can do the sorting.
That's the easiest approach.
Also events shouldn't contain to many categories. A performance impact
should not be high.
Relates: #8459
