Add rule for `crate_type = dylib`

We have `rust_shared_library` which is `cdylib` but we have no rules for `dylib` ([forum](https://users.rust-lang.org/t/what-is-the-difference-between-dylib-and-cdylib/28847)), should this be introduced?

Start by tracing the existing `rust_shared_library` rule and how it handles `crate_type = cdylib`; read the linked forum discussion to understand the distinction from `dylib`. Done should be defined as a reviewed decision and an implemented rule or explicit decision not to add one, with coverage for the requested crate type.

Written by the indexing model from the issue text.