v3.0.0

Major updates:

• Updated the schema for the service description object
• Updated the version of REST API from 2.3.4 to 3.0.0 and the version of API spec document from swagger 2.0 to openapi 3.0.0
• Added AsyncAPI spec documents
• Fixed CORS issue
• Updated MaxServiceTTL from 86400 to 2147483647 seconds i.e. from 1 day to (2^31 - 1) seconds or approx. 68 years, inspired my max TTL value for a DNS record. See RFC 2181