Base and Databricks environment

[RiccardoGrigoletto]

• Implementation of the class for managing the base and databricks environments.
• Duplicated and modified the original f-mnist example notebook to adapt to databricks.
• Created a notebook example for using maggy locally, the notebook train a simple NN using the Iris dataset.
• Deleted abstractEnvironment class, now the base class is Base in base.py.

[amacati]

Also, if you fix stuff from the comments you could mark the comments as resolved. That makes it easier to keep track of what still needs to be done.