feat (batcher): verify gnark proofs

[taturosati]

Batcher now verifiers different gnark proofs

To test:

1. Start anvil, batcher, aggregator & operator
2. Turn on debug logs with RUST_LOG=debug environment variable
3. From a different terminal, run:
   • make batcher_send_dummy_task PROVING_SYSTEM=plonk_bls12_381
   • make batcher_send_dummy_task PROVING_SYSTEM=plonk_bn254
   • make batcher_send_dummy_task PROVING_SYSTEM=groth16_bn254
4. See for each of those verification result is true on batcher