move flashbots/eth-sparse-mpt to a workspace crate

[dvush]

📝 Summary

Move all the code from flashbots/eth-sparse-mpt to this repo to make reth / alloy upgrades easier.

closes #210

💡 Motivation and Context

eth-sparse-mpt heavily depends on reth and alloy and this will make updates of the rbuilder dependencies easier.

---

✅ I have completed the following steps:

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

[github-actions]

Benchmark results for fc9b27f

Report: https://flashbots-rbuilder-ci-stats.s3.us-east-2.amazonaws.com/benchmark/fc9b27f-0ced7b0/report/index.html

Date (UTC)	2024-11-13T13:13:58+00:00
Commit	fc9b27f0a96615c09933b2c433a79933610b3f2f
Base SHA	0ced7b052e5aa8932b94e9009e70e112b24e9bdc

Significant changes

Benchmark	Mean	Status
MEV-Boost SubmitBlock serialization/JSON encoding	-28.73%	Performance has improved.