Remove yang.model.api.SchemaPath

org.opendaylight.yangtools.yang.model.api.SchemaPath is an addressing construct from our very first YANG parser. While it provided a common data structure, it did not provide any semantic meaning, as it is inherently ambiguous and a subject to interpretation – in fact different users of SchemaPath interpret its QName file differently.

In already has a explicit replacement in SchemaNodeIdentifier for the use cases covered by RFC6020/RFC7950 identification along the schema tree.

There still remain a number of entry points which expect it to be passed in and some amount of interpretation going on.

Introduce more powerful constructs to capture the remaining needs, migrate users, deprecate and remove SchemaPath.