Use Fastest Poseidon Implementation

[bhgomes]

We have a few different Poseidon implementations in the Manta ecosystem and we want to use the fastest one in production. Here are some goals for merging the implementation from Plonk-Prototype:

• Upgrade posiedon file to directory in manta-pay crate
• Keep the same interface that is defined in the current poseidon module, just upgrade the implementation (should not need to change any other files in manta-pay after the upgrade)
• Add tests for consistency with known Poseidon implementations
• Add in the parameter generation logic into the posiedon module and upgrade the parameters in the bin/generate_parameters.rs file (also remove the Sample implementation since it is not correct)
• Add a PR to manta-sdk for new parameters

NB: For this PR we only care about the R1CS implementation, not PLONK.

[tsunrise]

I will start this soon