AMQP Support

[RickWinter]

AMQP support in Azure::Core

- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4502
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4503
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4504
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4510
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4549
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4551
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4550
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4555
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4557
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4564
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4600
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4573
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/4841

### Known uAMQP issues
- [x] Message Sender Close method doesn't fully close the message sen
- [x] Message receiver Close method doesn't fully close the message receiver
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/5295
- [x] Message Session releases the channel number after sending the BEGIN session
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/5296
- [ ] https://github.com/Azure/azure-sdk-for-cpp/issues/5297

[LarryOsterman]

Detailed work items remaining:

• Redesign Azure::Core::Amqp::Message and Azure::Core::Amqp::Value to improve C++ usability - 5 days
• Doxygen support - 3 days
• Removed SetXxx APIs in favor of Options for Connection, Session, MessageSender and MessageReceiver. 3 days
• Add MessageSource and MessageTarget to MessageSender and MessageReceiver to improve terminus support.
• Removed SaslPlain authentication - 1 days
• Readme.md support - 2 days

Big ticket remaining items:

• Transparent credential expiration support
• Reconnect support

Outstanding questions:

• Do we really need connection and session as externally visible constructs given that the MessageSender controls opening and closing the connection/session?