Improve server support in Core Business

[defagos]

Description

This PR improves server support in Core Business. It also enhances server selection in the demo to support SAM as well as simulated locations in CH or abroad.

Changes made

• Make it possible to use any server conforming to the media composition data format and image resizing.
• Remove .mmf from Core Business server list (development tool). This is a breaking API change.
• Add support for SAM (prod, stage, test).
• Add support for simulated CH and WW locations for IL services (helpful to test geoblocking behavior).

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).

[defagos]

I revisited my original implementation which was providing closures to make it possible to build media composition requests and custom image resizing. In practice having a custom service posing as the IL is only useful internally anyway and requires deep understanding of endpoints and metadata formats. The closure-based API was likely overkill.

We currently only have SAM and MMF posing as the IL, as well as specific ways to simulate a user abroad. Those are implemented in the demo (and thus not provided in the Core Business public API). When SAM is released this mechanism will not be useful anymore anyway, so I guess it is better to keep things simple in the meantime.