new iOS/web extractors, image proxying done by views.py

- ythdd_globals.py - added helper function to get user-configured header
- ythdd.py - now checks for config.toml in work directory
- requirements.txt - add brotli, so that requests can decompress
innertube request

requirements.txt

@@ -11,4 +11,5 @@ Flask-SQLAlchemy>=3.1.1
 toml>=0.10.2
 Flask-APScheduler>=1.13.1
 requests>=2.32.3
-yt_dlp
+yt_dlp
+brotli>=1.1.0