[Deliverable] Implement RLN Onchain Tree Proof generation and verification in the Browser

[chair28980]

Owner: js-waku

Feature: RLN Relay

FURPS:

• F4. Light push client can be configured to generate proof for outbound messages.

• F5. Filter client can be configured to verify proof for inbound messages.

• S2. Browser edge nodes can be configured to verify and generate proofs.

Checklist:

• Specs: link to specs and/or API definition
• Code: link to GitHub issues/PRs/Epic
• Dogfood: link to dogfooding session/artefact
• Docs: links to README.md or docs.waku.org (TBD)