Cleanup

- 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

Merge pull request #3 from chrisidakwo/dev

Style format and refactorings

WIP: Initial release with standard payment, verify transaction, and r…

…efund transaction implemented.