reduce complexity by removing rc::Ref

[rbran]

Types that use rc::Ref only exists as References, so it makes sense to replace all occurrences of Ref<T> with T and move the Ref::inc_ref and Ref::dec_ref implementations to Clone and Drop.

[ElykDeer]

This is very interesting. I'll have to talk about this internally with the team to see if we want this. Thank you for the initial effort!