Replace the proof parameter with a limited id parameter.
A complete proof is not necessary to build a delegation. We only need the limited proof id and the proof master key.
The proof master key can be deduced from the exisiting privkey parameter when building a new delegation, and when adding a level to an existing delegation it can be found in the delegation (since D9564).
The RPC is no longer responsible for checking following potential errors:
- passing an invalid proof
- passing a private key that does not match the proof's public master key (when building a new delegation)
Depends on D9613