[wip] Kona ExEx

[merklefruit]

The Kona ExEx uses the Kona-derive implementation to traverse L1 blocks received from ExEx notifications to extract rollup blocks and validate them using either a trusted L2 execution client or a local engine API endpoint.

Current status

• initialize the local derivation pipeline
• wait for the reth L1 block to reach L2 genesis
• main loop: process each new L1 notification and step the derivation pipeline
• added AttributesValidator trait for switching from trusted to engine-api validation
• test sync with the TrustedValidator (similar to Kona's trusted-sync example)
• test sync with the EngineValidator once implemented

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It's possible for this example to be expanded to become a full L2 node, where the ExEx is caching all derived payloads and effectively building its own L2 state DB that way. Then, we don't need an L2 RPC anymore and can validate new payloads by building against the local state. Here is a short overview of the steps to reach this milestone:

• cache all derived payloads (how? can we use Kona's MPT impl with disk backend? need input on this)
• add ability to execute a full block, akin to performing engine_newPayload on local state (open Q: what about pre-bedrock blocks? presumably we will need some datadir to start with for chains like OP mainnet)
• (optional, long term): expose all the regular node APIs (from op-reth)
• (optional, long term): add the rollup node p2p overlay service to follow unsafe heads from the sequencer

Meta

• closes feat(kona): Execution Extension that uses Kona to derive L2 Payload Attributes #7
• iterates upon original work feat(examples): Kona Execution Extension reth#9030
• re-opened from previous forked remote [wip] Kona ExEx #10

[merklefruit]

Hera, a new OP stack rollup node, supercedes this PR and is being built in https://github.com/paradigmxyz/op-rs