Add example of CNN LSTM

[balandongiv]

Great work from the braindecode team. I believe this package will further help future researcher to dwell more into deep learning territory.

If I can offer a suggestion to the team to add extra example.
Perhaps, the team can consider to add example the implementation of CNN+LSTM using the sleep public dataset. I notice, the type of framework has been explored by many researcher for quite some time such as AutoSleepScorer.

But, this also might help potential user understand how the can extend further the application of braindecode by integrating various other DL technique.

[agramfort]

@balandongiv to add this model to our model zoo we would need to convert this model to PyTorch.

would you be willing to help?