194 basic support for subtitles and audio tracks

[StaehliJ]

Description

Add basic audio and text tracks selection to the demo. Forced subtitles are not handle in this version.

Changes made

• Give Flow access for Player.getCurrentTracks and Player.getTrackSelectionParameters
• Add helpers to enable and disable text tracks and audio tracks.
• Add helper to select a specific track.

Checklist

• Your branch has been rebased onto the main branch.
• APIs have been properly documented (if relevant).
• The documentation has been updated (if relevant).
• New unit tests have been written (if relevant).
• The demo has been updated (if relevant).
• All pull request status checks pass.