Letterboxd Custom PFPs wót casstanje

Enables the user to manually apply profile images to other letterboxd profiles, that are only visible for the user. This helps differentiate users who don't have profil icons on their profile.

To use:
- Open the extenstion popup
- Click "Add"
- Input letterboxd username (case-sensitive) of the user whose profile image you'd like to change
- Input URL of new profile image (can be any image of any size)
- Click "Save"
- The next time letterboxd is loaded, your chosen user's profile image should now appear as the new one