Remove any Hotel code left

[marcoacierno]

For 2025 attendees will book their hotel room via the hotel own website, meaning we don't need to support hotels anymore!

We should look into our codebase and see what code can be safely removed and isn't needed anymore. If in the future we will need hotels again, we will probably implement them using a better pattern, maybe the one we designed in https://www.notion.so/pythonit/Pretix-products-hotel-71077cf875ec4e55b6b057fdee4a5359