SPIKE: Can we auto-generate base (e.g Entity) code?

[jgadling]

Right now the Entity and File types are frozen as part of the platformics repo.

1. There are probably use cases where other applications need to add different base columns to base classes. Can we define a minimum base set of fields for a base Entity class and allow extra fields to be added in the schema? (this means codegen'ing the Entity types, probably)
2. Can codegen dynamically understand whether File is being used, and en/disable any File functionality from appearing in the GQL frontend if it's not used?
3. LinkML supports multiple base classes - for example we can have a BaseBook class that's extended by a FanatasyNovel class. SQLAlchemy and GraphQL support this pattern fine as well. Can we also support it in Platformics?

NOTE: Can we use similar solutions for Files?