[rpc] Remove template on RRef and add Type to RRef creation (#30630)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/30630
This remove template and all the specializations it have in rpc, we
universally use IValue as the inner value since we support making python
object to be hold inside IValue.
This will also ensure that we have the correct type information when
creating the RRef, we use the return type from the schema when creating
userRRef and OwnerRRef, it will enable IValue to always have the correct
type if the IValue is the RRef object (next PR)
Test Plan: Imported from OSS
Differential Revision: D19502235
fbshipit-source-id: 0d5decae8a9767e0893f3b8b6456b231653be3c5
