Implement v1 and v2 SQL schema in Rust

[ncalexan]

This ticket tracks "porting" the existing sqlite_schema.cljc code and definitions to Rust. In particular, handling the SQLite user version and schema upgrade paths to ensure the underlying SQL store is coherent.

This may require defining types for the part table, symbolic schema, ident<->entid maps, but we'll see as we go.

/cc @rnewman @joewalker

[rnewman]

Done enough, I think.