New template list feature: Document templates can be managed separately
from documents. Existing documents can be marked as templates.
Docker improvements: The Docker container image now includes XDebug. It
can be used to debug the extension with an external XDebug client.
PHPUnit improvements: PHPUnit is now included in the Docker container
image. A shell script (run-tests.sh) is provided to execute the tests
using the TYPO3 testing framework Nimut within the container. Tests
can also be debugged using XDebug.
