feature(meta, modulecodegen, runtime/orm): remove meta.ID interface

[fdymylja]

Currently the meta.ID interface allows to express IDs in multiple forms (raw bytes, string, uint64...). this was needed to offer a nicer API to fetch objects. But since we make use of modulecodegen to generate client APIs to interact with state objects which already abstract away the conversion from go type to byte for the KV we could possibly do without this abstraction.