Halo2 Circuit Workflow E2E

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Here are the TODOs for getting this feature done:

• Halo2 circuit to verify ECDSA signature normally
• Recover pk efficient trick.
• Halo2 Circuit using eff recover pk.
• API Wrapper for Halo2 Prover and Verifier
• Compile Rust lib into wasm
• Integrate the WASM with the UI using a WebWorker.
• Add the MerkleTree Gadget into the circuit
• Add Nullifier gadget into the circuit
• Benchmarking and optimization.