To register an on-chain config in Rust:
Defines the version of Libra Validator software.
Defines all the on chain configuration data needed by VM.
Defines and holds the publishing policies for the VM. There are three possible configurations:
State sync will panic if the value of any config in this registry is uninitialized
Trait to be implemented by a storage type from which to read on-chain configs
Trait to be implemented by a Rust struct representation of an on-chain config that is stored in storage as a serialized byte array