Remove Y800 and Y16 wich are the same as GRAY8 and GRAY16_LE
Add const to the GstVideoFormatInfo when used in argument
Add GRAY8 and GRAY16 pack/unpack functions
Add support for supporting chroma subsampling correctly in the pack
function.
Fill in the pack and unpack functions for most formats.
Add some missing pack/unpack functions to the orc file.