Re: [Multimedia] Video: updated support for VP9, Opus source media

Thanks to Giuseppe in ops & a bunch of other folks who have helped out, we've got an updated server configuration for the 'video scalers' that generate media transcodes, supporting VP9 video and Opus audio. Initially we have one server updated and in production, and the rest should follow by tomorrow. (Updated servers are also in place on the beta cluster.) This should make it possible for WebM files using VP9 video and/or Opus audio to work as fully first-class citizens in TimedMediaHandler, generating medium- and low-resolution transcodes in Ogg and WebM VP8. It should also fix Ogg audio files using the Opus codec to work consistently. Support for generating VP9 transcodes as well is in the code and just needs to be switched on -- I'll tweak that configuration once we've got the rest of the servers upgraded and have more capacity for batch runs. (I've got a client-side bot which I'll start once that's ready, to force all the files to generate over time.) -- brion