Add new API endpoints for media retrieval by country and enhance configuration

- Introduced `/api/tmdb` and `/api/collection/missing-locations` endpoints to the backend for improved media management.
- Added a new `get_media_by_country` function in the collection API to fetch media items based on country codes.
- Updated configuration to allow overriding *arr base URLs via environment variables for better flexibility.
- Enhanced frontend with a new `MissingLocations` component and integrated it into the routing structure.
- Improved the `CollectionMap` component to handle country selection and display media items accordingly.
- Added testing dependencies in `requirements.txt` and updated frontend configuration for testing support.

frontend/vite.config.ts

@@ -25,4 +25,9 @@ export default defineConfig({
       },
     },
   },
+  test: {
+    globals: true,
+    environment: 'jsdom',
+    setupFiles: './src/test/setup.ts',
+  },
 })