[Meta] ICC profile support

Task list:

• Add ancillary picture data
• Decoding via libavcodec
• Decoding via codec/jpeg.c
• Decoding via codec/png.c
• Display via vout_placebo
• Display via vout_opengl and libplacebo filter
• Encoding
• Fix demux/image.c
• Query ICC profiles on X11
• Query ICC profiles on Windows
• Query ICC profiles on macOS (help needed!)
• Plug display ICC profile into vout_placebo
• (Possibly) Plug display ICC profile into vout_opengl (via libplacebo filter)