Port y4m support from VTM
Port y4m support from VTM MR 2246 (jvet/VVCSoftware_VTM!2246 (merged)). It supports reading from y4m files and decode to y4m files based on file extension. It has no impact on bitstreams.
Port y4m support from VTM MR 2246 (jvet/VVCSoftware_VTM!2246 (merged)). It supports reading from y4m files and decode to y4m files based on file extension. It has no impact on bitstreams.