Improve Setup Instructions

[angel-daza]

Several participants reported that the Setup was not clear enough, here are some specifics that can be improved:

• Give clear instructions for windows.
• If the participant does not have the required specific Python version, there is no clear instructions for them to obtain it
• We should add checks that confirm that each step has run succesfully, so they are confident thins work before ocming to the workshop, or at least can point to a specific error if they need help the day itself
• The BERT-like models used in the Transformers lesson should also be downloaded during the setup