Experimental video support (web only)

[jleibs]

Initial experimental support for video. This will use the WebCodecs API to decode video.

To complete:

• APIs marked as experimental
• Publish forked version of mp4 library (re_mp4?)
• On native we just create an empty texture
  • Native Video support #7298

Known issue:

• Without a concept of duration, if only a video is logged the timeline won't expand to fill the duration of the video. The user will need to log some other place-holder content to fill in the timeline.
  • Design for "Video Frame References" #7272

[jleibs]

• Web-only video support #7261

[jprochazk]

Only thing missing here at the moment is publishing https://github.com/rerun-io/mp4, but we can wait until we're closer to the 0.19 release for that.

[emilk]

• Closed in favor of Publish rerun-io/mp4 as re_mp4 #7374 and other more granular video issues