SindyAutoencoders wrapped into a module + minor changes

[berberto]

Hi,
for my own convenience, I wrapped the code into a module, so that it can be installed via pip (added instructions to the README), and imported as a module in any working directory. I hope it's useful.
In addition:

• added a .yml file for installation of dependencies via conda
• created a .py file for every jupyter notebook in the examples folders, where sindyae is imported as a module.