Add a Macro to create tables from Swift Source?

[helje5]

Instead of basing the thing of a SQLite schema, with the new Macro feature in Swift 5.9 we could also generate the metadata required from the Swift structure itself. It probably wouldn't have much affect on the surrounding API, though maybe a Macro can't see related entities? Also the "Database" main structure wouldn't be generated? But there could be API for that.