Handle `#[sats(name = "Namespace.Thing)]` correctly in rust client codegen

[kazimuth]

Currently, rust clients generate incorrect code for sats name annotations with dots in them, e.g.:

https://github.com/clockworklabs/SpacetimeDB/blob/b1f80e0ffed492ab75795e12e055bac20823ca8f/crates/cli/tests/snapshots/codegen__codegen_rust.snap#L437-L443

This should be fixed and probably we should formalize these names as being actual lists of identifiers.