[Deliverable] TWN supports RLN onchain tree and deposits, existing memberships only

[Ivansete-status]

Owner: nwaku

Feature: RLN Smart Contract

FURPS:

• F3. RLN initialization only requires Web3 RPC calls, no blockchain events are needed.
• U2. User do not need to wait for merkle tree synchronization and building to start relaying
  or sending messages.
• P1. New node setup with an RLN membership can be ready to verify RLN proof within 5s,
  no matter the size of the tree (Vac-DST).
• +1. Smart Contracts are deployed on Linea Testnet.
• +2. TWN uses smart contracts deployed on Linea Testnet.

Checklist:

• Specs
  - API definition will be handled as part of RLN API
  - Logic worth spec'ing is covered in WAKU2-RLN-CONTRACT
• Code: link to GitHub issues/PRs/Epic --> issue: chore(rln-relay): deprecate tree sync strategy logos-messaging-nim#2924 | PR: feat: deprecate sync / local merkle tree  logos-messaging-nim#3312
• Dogfood:
  • TST Token
  • Getting membership
• Docs https://github.com/waku-org/nwaku-compose/blob/1efe84e72bffe4be8bae83ccf563c24c4c1cd1b0/README.md

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Roadmap definition

Summary

RLN smart contract is deployed on a testnet L2 and The Waku Network uses it for DoS protection. Nwaku uses the new contract ABI to get Merkle proof from the tree, instead of building the tree locally from contract events. Leading to faster setup and reduced resources.

[fryorcraken]

Ensure nwaku-compose docs are updated as part of this change.