docs: Scatterers

[Pwhsky]

• Changed relative imports to absolute.
• | instead of union type hints
• Examples use import deeptrack as dt.
• Method descriptions

[cmanzo]

• Replace Union[...] with | for compatibility with Python 3.10+.
• Ensure all classes support both Image and np.ndarray, including lists of each (list[Image] and list[np.ndarray]).
• Update type hints accordingly in method signatures and the Methods section of the docstring.
• Use built-in generics (list, dict, etc.) instead of List, Dict, etc., and remove their imports from typing.
• In Examples, always import deeptrack as dt and reference dt.Image, etc., instead of using Image directly.

[cmanzo]

Methods are not described in the docstring