Python: Remove deprecated BGL API

The API was in a deprecation state for many years now.
This API was not compatible with Metal nor Vulkan.

This also remove `Image.bindcode`.

Pull Request: https://projects.blender.org/blender/blender/pulls/140370

tests/python/bl_rst_completeness.py

@@ -23,7 +23,6 @@ import rst_to_doctree_mini
 
 # (file, module)
 modules = (
-    ("bgl.rst", "bgl", True),
     ("gpu.rst", "gpu", False),
 )