L2: offchain subdomain isAvailable

[pikonha]

Feature Request

We need to have a way to know whether domain is available for registration or not.

Describe Preferred Solution

Fetch it from the ENS Registry by relying on CCIP-Read.
We need to figure out a way of fetching a property of a nested contract through the storage layout mechanism provided by the EVMFetcher.

Architecture Diagram

QA Replication steps

1. call registerParams
2. receive an available boolean property