Handle blocked time ranges

[waliid]

Description

This PR allows us to manage some part of the stream which are marked as blocked/forbidden.

Changes made

• The item closure configuration has been replaced by an object (PlayerItemConfiguration).
• Seeking in a blocked range is not allowed anymore.
• Contents with a blocked part can now be played (excluding the blocked part).
• Blocked parts of a stream are jumped.
• On tvOS the blocked parts of the stream have been replaced by interstitials.
• A new section with time ranges has been added in the demo app.

Checklist

• [x] APIs have been properly documented (if relevant).
• [x] The documentation has been updated (if relevant).
• [x] New unit tests have been written (if relevant).
• [x] The demo has been updated (if relevant).