Make the codebase mypy-clean, drop dead media_utils and Pillow, rewrite README

tests/test_movie.py

@@ -1,6 +1,7 @@
 """Tests for the movie object and the pool layout it derives (src.core.movie)."""
 
 from pathlib import Path
+from typing import Any
 
 import pytest
 
@@ -79,8 +80,8 @@ class TestIdentityKey:
         assert identity_key(None, "Nějaký film", None) == "name-nejaky-film"
 
 
-def _movie(**kwargs) -> Movie:
-    base = {
+def _movie(**kwargs: Any) -> Movie:
+    base: dict[str, Any] = {
         "key": "tmdb-19995",
         "title": "Avatar",
         "year": "2009",