bitmapinfoheader: fix mask handling

The default masks to use and the proper storage to use was tested against the Windows player and some tooling of mock:// to generate the file.

The Windows player handles BI_RGB for all bit depths and BI_BITFIELDS with only one specific mask. Other masks are rejected.

The masks correspond to the memory layout of the same depth as BI_RGB and stored as Little-Endian values.

Deprecates !4249 (closed) now that the output to use is properly tested.

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v2 introduces a vlc_RGBChromaToMask() function. It will useful to get the masks from all the "fixed memory order" RGB chromas. They are needed by some muxers and video output.