Extend whois response words which show domain availability

# Problem
For many TLDs we can not check domain availability because both `domainWhoisAvailable` and `domainWhoisNotAvailable` not found in whois response (see [whois worker](https://github.com/codex-team/domain-checker/blob/master/backend/src/workers/whois/checkDomain.js)).

# Possible solution
Query each TLD for available and unavailable domain and write it somewhere. Than add words from raw responses to dictionaries.

Start by reading backend/src/workers/whois/checkDomain.js to see how domainWhoisAvailable and domainWhoisNotAvailable are used. Collect raw WHOIS responses for TLDs where availability is currently undetected, then update the response-word dictionaries so those domains are classified as available or unavailable.

Written by the indexing model from the issue text.