Add brotli content-encoding support (#2433)

Authored by: coletdjnz

yt_dlp/compat.py

@@ -170,6 +170,13 @@ def compat_expanduser(path):
     except ImportError:
         compat_pycrypto_AES = None
 
+try:
+    import brotlicffi as compat_brotli
+except ImportError:
+    try:
+        import brotli as compat_brotli
+    except ImportError:
+        compat_brotli = None
 
 WINDOWS_VT_MODE = False if compat_os_name == 'nt' else None
 
@@ -258,6 +265,7 @@ def windows_enable_vt_mode():  # TODO: Do this the proper way https://bugs.pytho
     'compat_asyncio_run',
     'compat_b64decode',
     'compat_basestring',
+    'compat_brotli',
     'compat_chr',
     'compat_collections_abc',
     'compat_cookiejar',