feat: zk light client

[dndll]

This is the first implementation of a zk light client, covering:

• full sync protocol
• parallel merkle verification proofs
• verifier contract, this is still very first pass, but is functional for the "one-shot" use case.
• one-shot command style "operator"

The focus here has been to cover as much of the basic functionality as possible, whilst there are still some improvements to be made on the contract and operator side of the light client for it to be fully functional for NEARDA.

The current verification circuit can take 128 proofs in batches of 4, this proves quite quickly and can cover roughly 4/MB * 128 in ~14mins on succincts current hardware. This allows rollups to post 512mb of provable data to NEARDA every 12 minutes. With folding we can further reduce the cost to verify this and we have some ideas for optimisation of the requests.

Additional functionality:

• rpc module specifically for light client operations
• light client protocol exposed, should be fairly usable by arbitrary dependents
• upgrades to nearcore deps, borsh and others
• cleans up test fixtures to support mainnet/testnet
• CI for tests, parallel testing

Also:

• bugfix in stake accounting

TODO:

• queued proof operator
• recursion on stepwise proofs
• lazy sync
• shared functionality protocol-crate <> circuit logic
• Improve solidity deployment scripts
• (maybe) expose the operator through the standard light client binary
• gas accounting works
• determine optimal batching size for verification and how to limit calldata issues. Removing account padding and such.