MQTT5 basic support

[Kuinox]

Client should be able to connect to a mqtt5 broker and can use the following feature:
4.10 Request / Response
4.12 Enhanced authentication

3.1.2.11.8 User Property
3.1.2.11.9 Authentication Method
3.1.2.11.10 Authentication Data
3.3.2.3.5 Response Topic
3.3.2.3.6 Correlation Data
3.3.2.3.9 Content Type