Improve dependencies (optional dependencies, docs, tests)
Currently the dependencies are not really well documented/handled.
Add a file for doc dependencies (sphinx etc, see CI file)
Add a file for test dependencies (sphinx etc, see CI file)
Possibly integrate this in pyproject.toml
Consider dropping the explicit requirement on pyside2 and introduce some way of saying that one of pyside2 and pyqt5 is required (possibly pyside6/pyqt6 when support for it).
Edited by Oscar Gustafsson