feat: add .env configuration with example template and update documentation

Add .env.example template with all configuration options (Radarr, Sonarr, SABnzbd). Move environment variables from docker-compose.yml to .env file for easier configuration management. Add .gitignore for .env, data/, and Python cache files. Update README with setup instructions for copying .env.example and configuring services. Replace hardcoded volume paths with environment variables in docker-compose.yml.

docker-compose.yml

@@ -5,32 +5,13 @@ services:
     restart: unless-stopped
     ports:
       - "8099:8099"
-    environment:
-      RADARR_URL: "http://radarr:7878"
-      RADARR_API_KEY: "CHANGE_ME"
-
-      # Optional: Sonarr aktivieren (auskommentieren und Werte anpassen)
-      # SONARR_URL: "http://sonarr:8989"
-      # SONARR_API_KEY: "CHANGE_ME"
-
-      # Optional: SABnzbd aktivieren
-      # SAB_URL: "http://sabnzbd:8080"
-      # SAB_API_KEY: "CHANGE_ME"
-
-      # Pfad, den Radarr in seiner API meldet:
-      RADARR_MEDIA_PATH: "/data/filme"
-
-      # Pfad derselben Dateien INNERHALB dieses Containers:
-      LOCAL_MEDIA_PATH: "/media/filme"
-      # SONARR_MEDIA_PATH: "/data/serien"
-      # LOCAL_SERIES_PATH: "/media/serien"
-
-      DB_PATH: "/data/cache.db"
-      LOG_LEVEL: "INFO"
+    env_file:
+      - .env
     volumes:
       # Host-Pfad deiner Film-Library -> interner Dashboard-Pfad
-      - /nesflix/filme:/media/filme:ro
-      # - /nesflix/serien:/media/serien:ro
+      - ${FILM_MEDIA_VOLUME}:/media/filme:ro
+      # Sonarr aktivieren, wenn SERIES_MEDIA_VOLUME gesetzt ist:
+      # - ${SERIES_MEDIA_VOLUME}:/media/serien:ro
       - ./data:/data
     networks:
       - media