Ogdf-python

- auto-enable ogdf-python-widget
- add ogdf info dict (`python -m ogdf_python.info`)
- add mybinder links
- make OGDF_INSTALL- and -BUILD_DIR non-exclusive, print search path on import error
- set NDEBUG depending on OGDF debug mode
- migrate build system to hatchling, remove cppyy version cap
- fixes for ClusterGraphObserver, -Attributes
- fix exception on empty docstring

minor fixes and sync with [OGDF 2022.02 (Dogwood)](https://github.com/ogdf/ogdf/commit/7596a518d2b8a964523c2bbd86af360aa405c6cf)

restructure pythonizations and add further goodies and examples

- fixed G.nodes(.byid)
- add node/edge/adjEntry to string
- fix BUILD_DIR ending with a slash
- enable doxygen URLs
- add jupyter cell magics
- add interactive-bfs and dfs examples
- fix SVG rendering compat with OGDF 2020.02 (Catalpa)

multiple fixes, added doxygen hints for missing imports