More Detailed Explanation of Parameters

The propulate parameters are explained to a degree in the [API Reference](https://propulate.readthedocs.io/en/latest/autoapi/index.html) and throughout the docs. However, without an understanding of propulate's inner workings, it can be hard to understand how they affect the hyperparameter search and when/why/how one should adjust them.
For example, it is clear that `num_islands` sets the number of islands, but how does one know how many islands are needed?

It would be nice to have a docs page where these essential parameters (`generations`, `num_islands`, the probabilities,...) are explained in more detail, including reasonable default parameters and (if possible) some intuitions/rule of thumbs on how they affect the HP search.

Start with the API Reference and the existing documentation to identify the essential parameters, including generations, num_islands, and probability settings. The documentation is done when it explains their effects on hyperparameter search, gives reasonable defaults, and provides practical guidance or rules of thumb for choosing values.

Written by the indexing model from the issue text.