added generic branch example

[scud-soptim]

Added Example and Documentation for Issue: #729

Changes proposed in this PR include:

• Added usage examples for the Generic Branch.
• Included documentation on how to use the Generic Branch with CIM/CGMES datasets.

[TonyXiang8787]

Hi @scud-soptim,

Thanks for the example. We forgot to add the new notebook to the table of content in the documentation. Can you create a new PR to do it? See below

power-grid-model/docs/index.md

Lines 85 to 96 in 6d8caab

	```{toctree}
	:caption: "Examples"
	:maxdepth: 2
	examples/Power Flow Example.ipynb
	examples/Serialization Example.ipynb
	examples/State Estimation Example.ipynb
	examples/Short Circuit Example.ipynb
	examples/Validation Examples.ipynb
	examples/Make Test Dataset.ipynb
	examples/Asymmetric Calculation Example.ipynb
	examples/Transformer Examples.ipynb
	```