Add support for "Skip intro"/"Skip credits"

[MGaetan89]

Pull request

Description

This PR adds new API to be notified when reaching the opening and closing credits.

Changes made

• Added the PillarboxPlayer.Listener.onTimeIntervalChanged(SkipableTimeInterval?) callback.
• Added the Player.getCurrentTimeIntervalAsFlow() extension.
• Added the Player.getTimeIntervals() extension.
• Added the Player.getTimeIntervalAtPosition(Long) extension`.
• Added the Player.getCurrentTimeIntervalAsState() extension.
• Refactor ChaptersTracker to be more generic.

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.

[github-actions]

Code Coverage

Overall Project	46.59% -0.66%	🟢
Files changed	37.44%	🟢

Module	Coverage
:pillarbox-core-business	85.02%	🟢
:pillarbox-player	47.18% -1.15%	🟢
:pillarbox-ui	0% -0.62%	🟢

Files

Module	File	Coverage
:pillarbox-core-business	SRGAssetLoader.kt	87.04%	🟢
	Chapter.kt	54.42%	🟢
:pillarbox-player	Asset.kt	100%	🟢
	PillarboxSessionCommands.kt	100%	🟢
	PillarboxMediaSource.kt	90.94% -0.34%	🟢
	Player.kt	90.74%	🟢
	PlayerCallbackFlow.kt	78.03%	🟢
	PillarboxExoPlayer.kt	77.16%	🟢
	PillarboxMediaController.kt	0% -2.33%	🟢
	PillarboxMediaSession.kt	0% -10.97%	🟢
	PillarboxPlayer.kt	0%	🟢
:pillarbox-ui	ComposablePlayer.kt	0% -3.47%	🟢