Add tooling to infer a computable definition from an expansion

[brynrhodes]

Some environments require computable value set definitions, rather than just expansions. In this case, we need tooling that can infer a computable definition from an expansion.

Ensure that the tooling will throw if the expansion is partial (i.e. it's a page of a complete expansion)

Add a valueset-warning that the compose was inferred from the expansion and should not be considered an authoritative computable definition of the value set.