Add support for token-protected and DRM-encrypted URLs to the demo

[defagos]

Description

This PR adds support for a wider range of URL inputs in the demo app:

• URLs protected by SRG SSR token.
• URLs protected by SRG SSR encryption (require certificate URL).

Preview

Changes made

• Add Core Business player item construction APIs to make it possible to create SRG SSR token-protected and encrypted player items. Since metadata is not retrieved tracker adapters are not automatically attached to such items.
• Add picker to the demo letting the user choose which type of input is provided (URL, URN, token-protected URL, encrypted URL).

Checklist

• 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).