feat(l2): bench job

[xqft]

Motivation

Continously (on each push to main) prove an Ethereum Mainnet block to test and benchmark ethrex-prover.

Description

• adds job to prove an L1 block using the bench crate
• post the gas rate (Mgas/s) into gh pages with the github benchmark action.

[github-actions]

Lines of code report

Total lines added: 21
Total lines removed: 0
Total lines changed: 21

Detailed view

+-------------------------------------------+-------+------+
| File                                      | Lines | Diff |
+-------------------------------------------+-------+------+
| ethrex/crates/l2/prover/bench/src/main.rs | 116   | +21  |
+-------------------------------------------+-------+------+

[xqft]

Successful run: https://github.com/lambdaclass/ethrex/actions/runs/14803522566/job/41567485293

TODO:

1. Add ETHREX_L2_RPC_URL secret
2. Add system info about runner

[xqft]

Another option is to cache a block, but in that case we would be omitting part of the flow and we may not catch some bugs