Support specifying namespaced types

[vyshane]

We are using gRPC-Web and it generates types similar to the following from protobuf definitions:

export namespace Todo {
  export type AsObject = {
    id: string,
    title: string,
    completed: boolean,
  }
}

export namespace GetTodoRequest {
  export type AsObject = {
    id: string,
  }
}

I would like to be able to call the intermock CLI with the option --interfaces "Todo.AsObject" "GetTodoRequest.AsObject".

Currently I'm only able to run --interfaces "AsObject", which only generates a mock for the very last AsObject type that intermock finds, i.e. GetTodoRequest.AsObject.