[Plugin Request] Support video tag/fourcc hvc1

[arolson101]

Background: macOS Finder's QuickLook will play h264 and h265 videos, but only if they have the video tag set to "hvc1" (ffmpeg command line option: "-tag:v hvc1" or "-vtag hvc1"). ffmpeg sets the vtag to "hev1" by default.

It would be great if there was a flow plugin to check the vtag, as well as an option to set it (or just set it by default) in the transcode.