Allow importing to/ importing from repositories of the same name but differing architectures

In !74 (merged) the capability of importing to/ importing from a named repository has been implemented. However, the implementation currently only returns the first matching repository.

As we will have repositories of the same name (e.g. default), but differing architectures (e.g. x86_64 and aarch64) we will need to be able to become more specific (e.g. by providing the targeted architecture).