Added AV1 video encoding in &wcap
Supports 8-bit and 10-bit format main profiles.
AV1 is newer codec that in theory should allow smaller output file size for similar quality (or better quality for similar output file size). In practice the quality and availability depends on driver and h/w support. Probably fine on Nvidia, but not really recommended on AMD (worse quality than alternatives). Does not work on Qualcomm (GPU driver crashes). Windows provides no software fallback for encoding on CPU, must have h/w support to enable AV1.