chore: replace std mutex with parking lot

[mattsse]

📝 Summary

replaces std sync primitives with parking_lot's

💡 Motivation and Context

parking_lot's primitives are more performant and don't come with lock poisoning, hence no unwrap

https://docs.rs/parking_lot/latest/parking_lot/type.Mutex.html#differences-from-the-standard-library-mutex

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✅ I have completed the following steps:

• Run make lint
• Run make test
• Added tests (if applicable)

[github-actions]

Benchmark results for 9fb9646

Report: https://flashbots-rbuilder-ci-stats.s3.us-east-2.amazonaws.com/benchmark/9fb9646-39f4903/report/index.html

Date (UTC)	2024-12-06T13:51:50+00:00
Commit	9fb96462c93f2555efd0e29da8a2691cc1f06b97
Base SHA	39f4903805f61af8e73cfe84237f80e98e15e867

Significant changes

Benchmark	Mean	Status
MEV-Boost SubmitBlock serialization/JSON encoding	5.77%	Performance has degraded.