Download image sequence as video/MP4

[ShrimpCryptid]

Use Case

@jcass11 and @vianamp requested the ability to directly download MP4 video for use on presentations and sharing.

Acceptance Criteria

• Users can click a button to initiate a recording.
• Once the recording is finished, an encoded MP4 video will be downloaded to the user's Download directory (or the user will be prompted for a download location).
• Naming should default to the same as the existing RecordingControls.

Details

• Similar to [Record Movies] Enable SharedArrayBuffer for non-dev environment simularium/simularium-viewer#252, which is running into technical issues with built-in browser security policies.

[toloudis]

Also potentially relevant: simularium/simularium-viewer#251