Ethereum Integration

[kayabaNerve]

This is not ready for production. It does a lot of the leg work on the actual integration, and is far along enough I'd like to start running the CI on it.

In general, what needs to be done:

1. Update the documentation
2. Implement fee handling
3. Have user specification of the gas limit (instead of a constant)
4. Have an additional service to publish TXs through
5. Build a better pattern for event retrieval
6. Move ScannerEvent::Completed from a tuple to a struct
7. Re-define key_for_any_change to a stricter definition, as currently expected
8. Make a proper trait for Eventuality Completions
9. Handle top-level transfers in the processor

What has been done:

1. Moved to alloy (Replace ethers-rs with alloy #331), including developing a new transport around our own simple-request
2. Adds deterministic deployment of the Router, offering efficient location without DoS risks
3. Adds a Sandbox to make aggregated calls with
4. Fleshes out the Router
5. Makes the Scheduler generic to the processor (starting the road on Processor modularity #289)
6. Replaces transaction signing with eventuality completion, a higher layer of abstraction
7. Moves creation of refund and forwarding plans into the scheduler