Rewrite examples in plain script (no class)

[hsalehipour]

It might be better to avoid defining classes and instead use simple scripts to run all experiments. Additionally, we should treat the examples as tutorials, providing plenty of comments and detailed descriptions for each step.

However, it would be helpful to keep the lid-driven cavity example in a class format since we have a distributed version that inherits from it. This will demonstrate an alternative way of structuring examples.

The lift and drag scripts in wind tunnel example can also be improved.

[sambaPython24]

@hsalehipour That would be a good idea, for example explaining directly in the code such as the simple flow past sphere what the e.g. the self.stepper function is doing and what arguments it is taking. There is an error in this example and it is difficult to debug, since the docstring is also limited (e.g.

Signature: simulation.stepper.__call__(*args, callback=None, **kwargs)
Docstring: Call self as a function.
File:      [~/path_to_package/python3.12/site-packages/xlb/operator/operator.py](https://file+.vscode-resource.vscode-cdn.net/home/emonds/Dokumente/FlowSimulation/~/anaconda3/envs/pytorch3D/lib/python3.12/site-packages/xlb/operator/operator.py)
Type:      method

)