x11: Support the CTM (color transform matrix) RandR property

When supported, this property allows the window system to apply a 3x3 color
correction matrix in order to transform colors from the window system's native
color space to the measured color space of a display device.

Query for this property and set the 'supports-color-transform' property in the
GetResource reply. Add support for the SetOutputCTM DBus method and plumb that
through to the server's CTM property.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1048>

src/backends/meta-output.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2017 Red Hat
+ * Copyright (C) 2020 NVIDIA CORPORATION
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
@@ -89,6 +90,7 @@ typedef struct _MetaOutputInfo
   int backlight_max;
 
   gboolean supports_underscanning;
+  gboolean supports_color_transform;
 
   /*
    * Get a new preferred mode on hotplug events, to handle dynamic guest