Deprecate `gfxdraw` but keep the functionality

[damusss]

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This PR officially deprecates the gfxdraw module, but the functionality is intact. We can remove gfxdraw in pygame-3 or later.

The following features must be added for this PR to leave draft:

• pygame.draw.aaellipse
• pygame.draw.aapolygon

pie was deprecated with no replacement (but one can use arc+line) and so did textured_polygon. If you disagree, tell me about it.

GFX_DEPRECATED_VERSION will be replaced when this is ready to be reviewed.