Implement a fully code-driven example and have it part of CI

[andy31415]

This has significant prerequisites:

• Full ember decoupling in libCHIP (so that only a DataModel::Provider is required)
• At least Minimal Root endpoint cluster conversion to be code driven (BasicInfo, Access Control, GroupKey Management, General Commissioning, Administrator Commissioning, Node Operational Credentials) - see Convert cluster implementations to be unit testable and have a consistent design #36538
• Have ability to define a datamodel purely from code. Expect initial version to be some merge of "metadata" (in some format) + AttributeAccessInterface + CommandHandlerInterface

This issue should be kept as a tracker of what we are missing until we can have such an example and keep fixing code until this example is feasable.