Refactored the whole scraper

A lot of stuff was changed in the last commits, I will try to summarize:

• The stations are persisted now through a JSON file.
• The stations selection has fuzzy finding features now.
• The scraper module has been rewritten entirely.
• The scraping mechanism is not based on headless browser anymore, making it less flaky and lighter, as it only uses the requests library.
• The bot module is a complete mess, but it works and now persists the user input using Pickle.