[WIP] Feature networkx implementation in IfcGraphViz.py

[seb-esser]

Dear @jakob-beetz

First of all, thank you for making the notebooks in this repository publicly available. When browsing through the current methods provided in the repository, I found your comment about a possible extension towards the networkX package: ## If you are reading this, and are interested, please helpme to reimplement this in networkx!

This pull request implements some first ideas on how I could imagine a networkX implementation. I am happy to further contribute here but first like to get an idea of your vision. To my current understanding, two options exist to refine the current methods:

• Option 1: replace graphviz library and manage both, the graph extraction and the visualization via networkX
• Option 2: keep graphviz for visualization but extend the networkX extraction to demonstrate some graph-related concepts in IFC (e.g., cycle-free graphs, ...)

I am looking forward to exchanging ideas on these topics. I have taken great benefit from all developments around IfcOpenShell and particularly from all the resources that helped me learn to interact with IFC files in Python. Thus, I am motivated to share some pieces of my current knowledge to improve materials for the next generations ;-)

Best regards from Munich Sebastian