POC Start playback at a given position inside a Playlist

[StaehliJ]

PoC details

Allow integrators to easely seek at a given position inside a playlist. For example, having multiple items inside the playlist with position history and when seek back or seek next item, it will start up at the history position.

Currently ExoPlayer/Media3 doesn't support it. google/ExoPlayer#6373

• Add a demo with a playlist with history support. Try to make the feature without player changes
• We could add a start Position or position when loading the media.