Update ProofSystemCompiler to use new acvm preprocess interface

[vezenovm]

The current interface trait being used for Marlin is deprecated. We should update the Marlin backend to use the new preprocess interface as well as the proving and verification methods that take in the respective keys outputted from preprocess.

The methods inside arkworks_backend are going to have to be updated as well to reflect this change, including a general strategy for using a SRS. The arkworks backend currently constructs the srs on every prove and verify along with generating the proving and verification keys.