v1.1.0 - Mx Record Validation

GuardPost now validates whether a domain can receive email by checking for the presence of MX (Mail Exchange) records via DNS using Java's built-in JNDI (Java Naming and Directory Interface) interface.

New Utility Class: EmailUtils

Introduced EmailUtils to handle email parsing logic (extracting domain from email) to simplify and isolate logic from service layer for better testing and reusability.

Codebase Refactoring

Refactored codebase so that the EmailValidationController now strictly handles HTTP logic and EmailValidationService focuses solely on business logic. Mx record checking and domain parsing were delegated to their appropriate classes/services as well.

Not only are emails syntactically validated, but now non-functional domains are caught before storing/using them. JNDI implementation sets up this codebase for future DNS-based features as well.