Enable debit/credit card transactions and charge validation

• Enable transactions with credit/debit cards
• Handle card transaction authorization processes
• Added charge validation for validating bank account and/or debit/credit card transactions
• Added encryptTransactionData() function to encrypt transaction charge data
• Moved ChrisIdakwo\Support\Entity to a new namespace ChrisIdakwo\Support\Entities\Entity
• Added entity classes to support easy typing of response objects
• Cleaned up codebase

New support for several Rave services

• Bank account payment, transfer, and verification
• BVN verification
• Debit card preauthorization charge, cancellation, and refund
• Moved validators into a new namespace
• Refactored Transaction entity. Added extra fields to allow the class to be easily used to format responses from other services with similar response JSON structure.
• Added a few tests. Others pending.