VLC.ONL ffmpeg.wasm source and license notice

The browser video converter distributes @ffmpeg/ffmpeg 0.12.15 and the
single-threaded @ffmpeg/core 0.12.10 WebAssembly build reviewed at upstream
commit f876f907c7e9b9bf51d4ed0b913a855a63ae63fc.

The JavaScript wrapper is licensed under the MIT License. The WebAssembly core
is licensed under GPL-2.0-or-later. Copies of both license texts are available
beside this notice. The corresponding ffmpeg.wasm source, build scripts and
package sources are available at:

source/ffmpeg-wasm-f876f907-source.tar.gz

Upstream source: https://github.com/ffmpegwasm/ffmpeg.wasm/tree/f876f907c7e9b9bf51d4ed0b913a855a63ae63fc

The build definition pins FFmpeg n5.1.4 and the linked library versions. Their
upstream source locations are recorded in the included Dockerfile. VLC.ONL
will provide an additional copy of the full corresponding source on request
without charge. Contact editor@vlc.onl and identify @ffmpeg/core 0.12.10.

Checksums for every distributed runtime file and the source archive are in
manifest.json. This offer is valid for at least three years from the last date
VLC.ONL distributes this build.