docs: add tutorial / how-to-guide for embedding time-series data, e.g., using causalCNNs

[janfb]

We now have a bunch of new embedding nets to process sequential data, e.g., the CausalCNN (see also #1499 #1494 #1512 )

It would be great to add a short how-to-guide for using these embeddings, e.g., using a well-known time-series model like the SIR or Lotka-Volterra.

See also #1499 (comment) for inspiration.