Support playback from Cockpit log files + video recordings

[ES-Alexander]

#582 introduced logging of (some of) Cockpit's outputs. It would be very handy to allow using those as a dive replay source with a nicer interface than is possible with a subtitle file.

As an extension of that idea, it would be super convenient to

• allow the user to create an "Export" Profile which gets saved together with video recordings and the Cockpit logs,
  • ideally in a way that Cockpit can be directed to the folder of stuff and load it all together for playback.

That way the data owner could decide how they want the widgets and whatnot to be displayed, and then they can send the folder of stuff to external parties who could do playback of it on a web-hosted version of Cockpit (without needing anything installed outside of a browser).

Furthermore,

• we could allow specifying a cloud storage URL (e.g. google drive, BlueOS cloud in future, etc) to load the data from, to make it even easier,
• potentially even in the form of a pre-filled URL so the "client" goes to the specified URL, which loads Cockpit and automatically fetches the data they wanted to play back.

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• This would likely require a new "play/pause" mini-widget, that could be used predominantly in Export profiles, for pausing the current log and video playback.
  • In a similar vein, we may also want to add a time-based slider widget that shows the current timestamp, allows changing the timestamp (and the playback rate), and potentially also displays recorded events of interest and the like (or some kind of indicator of that from the telemetry / processing the video)
• Existing widgets that do some kind of data processing/formatting may need to add a "playback" option that allows accepting a pre-processed output value instead of a standard input value
  • We should define a consistent API for a widget to support this functionality, along with adding other file types to playback (e.g. for a sonar viewer)