Fix color in -q -F

and convert `ydl._out_files`/`ydl._allow_colors` to `Namespace`

Closes #3761

yt_dlp/utils.py

@@ -5322,8 +5322,20 @@ class classproperty:
         return self.f(cls)
 
 
-def Namespace(**kwargs):
-    return collections.namedtuple('Namespace', kwargs)(**kwargs)
+class Namespace:
+    """Immutable namespace"""
+    @property
+    def items_(self):
+        return self._dict.items()
+
+    def __init__(self, **kwargs):
+        self._dict = kwargs
+
+    def __getattr__(self, attr):
+        return self._dict[attr]
+
+    def __repr__(self):
+        return f'{type(self).__name__}({", ".join(f"{k}={v}" for k, v in self.items_)})'
 
 
 # Deprecated