Support Kotlin Annotation Customization

[snowsignal]

Kotlin should have both inline and .toml-level configuration to support annotations on types, similar to how Swift supports decorators.

For example:

#[typeshare(kotlin(annotations = "Serializable, Immutable, Parcelize"))]
struct MyType {
  value: String
}

becomes:

@Serializable
@Immutable
@Parcelize
data class MyType {
  val value: String,
}