doc: add Verifier Contract section to README (#290)

* Add `Verifier Contract` section to README.

* Add generated file descriptions when running aggregation tests.

README.md

@@ -92,6 +92,20 @@ sh scripts/gen_full_chunk_proofs.sh BATCH_INDEX
 - `docker/chunk-prover` is used to build and run GPU chunk-prover.
 - `docker/mock-testnet` is used to build and run GPU mock-testnet (inner-prove or chunk-prove).
 
+### Verifier Contract
+
+Both YUL and bytecode of verifier contract could be generated when running aggregation tests (`make test-agg-prove`). After running aggregation tests, a new folder is created in `integration` folder of scroll-prover and named as `agg_tests_output_multi_DATE_TIME`. It contains below files:
+
+- Chunk protocol: `chunk_chunk_0.protocol`
+- Chunk VK: `vk_chunk_0.vkey`
+- Batch VK: `vk_batch_agg.vkey`
+- Verifier YUL source code: `evm_verifier.yul`
+- Verifier bytecode: `evm_verifier.bin`
+
+The YUL source code is generated by params, VK and num instance of proof, could reference [gen_evm_verifier function](https://github.com/scroll-tech/snark-verifier/blob/develop/snark-verifier-sdk/src/evm_api.rs#L121) in snark-verifier.
+
+The verifier bytecode is compiled from YUL source code, it invokes Solidity compiler (`0.8.19` as mentioned above) command line with specified parameters, could reference [compile_yul function](https://github.com/scroll-tech/snark-verifier/blob/develop/snark-verifier/src/loader/evm/util.rs#L107) in snark-verifier.
+
 ## License
 
 Licensed under either of