Implement support for Integrated Terminals

Problem/Motivation

CardPointe supports integration with terminal payment devices and their Integrated Terminal API.

Supporting this would allow POS implementations to accept MSR, EMV, and NFC payments.

This implementation provides:

1. An Integrated Terminal API implementation for the most common methods. (listTerminals, terminalDetails, connect, ping, dateTime, display, authCard, disconnect)
2. Extended configuration on the CardPointe Gateway to configure the Integrated Terminal API
3. A terminal entity to manage terminals.
4. An additional payment method type for terminal payments.
5. A UX for selecting a terminal and initiating a card transaction. (Note: this is a basic implementation. Most likely, site implementations will have a greater POS implementation, including mapping registers and a mapping of registers to terminals.)
6. Exceptions implementation to handle cases like: terminal in use, terminal not available, etc...