Added alternative embedding code for comparison.
Use custom embedder instead of sally to make sure that we don't get any collisions. Also, do TFIDF directly. Adapted knn.py in joern-tools accordingly.
Use new python-joern feature to inject steps into the server. Use the new embedder from joern-tools.
Use apiEmbedder and knn programatically rather than through the shell.
Do not store inc/dec operators
Do not store primary expressions
The decision whether a expression is stored or not depends now on the expression itself
Do not store NULL