Sinsemilla hash function in Plompiler

See https://zcash.github.io/orchard/design/circuit/gadgets/sinsemilla.html. Spec: https://zips.z.cash/protocol/protocol.pdf#concretesinsemillahash

Keywords:

• 4 times less efficient than Poseidon and Rescue in circuits
• 19 times more efficient than Rescue outside of a circuit

Pros:

• Standard cryptographic assumptions