This PR moves image retrieval to the player level, making implementation of custom asset loading publishers even simpler.
Changes made
Replace images with image sources which can be used to provide either an image or a URL (URL requests were considered but will be added later if really meaningful).
Implement publishers for image sources, chapters and PlayerMetadata so that each of them can published updates of themselves when images are loaded.
Remove image retrieval from Core Business entirely.
Update enum style for consistency.
Add missing image width constant.
Use default URL sessions (hopefully not needed anymore, see #272).
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).
Description
This PR moves image retrieval to the player level, making implementation of custom asset loading publishers even simpler.
Changes made
PlayerMetadataso that each of them can published updates of themselves when images are loaded.Checklist