feature request: Proof verifier in Solidity

[kumavis]

perhaps non trivial :stuck_out_tongue_winking_eye:

[Divide-By-0]

Once we get this pr merged, we should just be able to generate a Solidity verification circuit from the circom! The issue is that its between 200-300k gas, but hopefully with things like SnarkPack/zk rollups, that can be made lower.