* Add missing dependency to composer package `typo3/cms-install`.
As UpgradeWizards use API of the package.
* Migrate deprecated PHPStan configuration options
* Adapt expected HTML output within functional tests
As TYPO3 changed actual generated HTML.
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 event right before
it is persisted within Destination Data One import.
This for example allows to alter dates, prices, etc.
Improve handling of missing end time in dates.
The clean up task had an issue to clean up to many files.
It didn't check if a file that could be deleted
because one event got deleted, was still in use by another event.
Relates: #10499
The existing code didn't work with the provided data.
We added a new test case to cover the situation.
We adjusted the existing code to check on the actual rel value instead
of the keys.
