Improve metadata delivery

[waliid]

Description

This PR allows us to improve the metadata delivery.

Changes made

• The MetadataAdapter has been removed.
• The comScore SDK has been updated to 6.12.3
• All content providers for radio live streams have been added to demo app.
• A timeRange for chapter has been added.
• A new struct Episode has been introduced.
• The display format of season / episode has been localized.
• A new protocol AssetMetadata has been added.
• All chapters images are retrieved during the initialization of items.
• New structs ChapterMetadata and EpisodeInformation have been introduced.
• The protocol PlayerItemMetadata has been removed.
• The PlayerMetadata has been improved to contains all stuff related to the metadata.

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).