Conversion from new ModuleDef -> existing TableSchema

[kazimuth]

This will allow using the new ModuleDef validation code wherever we ingest RawModuleDefs and convert them to TableSchema etc in the codebase.

Requires an integration test that the following paths:

old: RawModuleDefV8 -> Vec<TableSchema>
new: RawModuleDefV8 -> RawModuleDefV9 -> ModuleDef -> Result<Vec<TableSchema>>

produce equivalent output (identical results, unless the new path rejects something that the old path accepts).