Prover and Verifier are **not** type-safe

[ureeves]

Describe what you want implemented
While these structures are type-safe while in memory, the moment they're serialized and subsequently de-serialized, they cease to be so. This means that it is possible, for example, to de-serialize a Verifier<C1> from a payload of Verifier<C2> with C1 != C2.

Describe "Why" this is needed
Type-safety is not a requirement per-se, but since it is one of the design goals it should probably be taken seriously.

Describe alternatives you've considered
A solution for this would be to include information about the circuit type with the serialized Prover and Verifier.

Additional context
In the process of migrating rusk-abi, I came understand that the choosing of the circuit was made more difficult by the newer plonk API, but also realized how serialization can easily be abused.

[marta-belles]

Not applicable anymore.