libvpx: enable high bit depth support and cleanup package
This enables support for encoding VP9 video with 10 and 12 bit color depth, by default it was built only wih 8 bit depth support. Although these pixel formats are rarely used in consumer-grade media, they are fairly popular among videophiles.
Also this enables VP9-specific postprocessing and temporal denoising algorithms for better quality of decoded frames.
Test Plan: Transcoded video from H264 with YUV420P (8 bit depth) pixel format to VP9 with YUV420P10LE (10 bit depth) pixel format with FFmpeg. Checked that mpv and VLC can decode and render the resulting video.
Reviewers: Triage Team, JoshStrobl
Reviewed By: Triage Team, JoshStrobl
Differential Revision: https://dev.getsol.us/D9305