Kafka Bridge message protocols

User stories

• As a Developer, I want to use HTTP protocol to send / receive messages to / from Kafka to make it eaiser to use Kafka from applications which do not speak Kafka protocol
• As a Developer, I want to secure and manage the HTTP Bridge using Red Hat 3Scale.
• As a Developer, I want to use AMQP protocol to send / receive messages to / from Kafka to make it possible to communicate with Kafka from my existing AMQP enabled applications
• As a Developer, I want to use MQTT protocol to send / receive messages to / from Kafka to make it possible to use Kafka in my IoT applications

The current bridge implementation is tied to the AMQP protocol only so that it's the only supported protocol for bridging to Apache Kafka.
Having multi-protocol support (pluggable in some way) could be useful for bridging other different protocols other than AMQP (i.e. MQTT for IoT use cases, HTTP, ...).
It terms of effort it means to refactor the bridge in order to have source/sink endpoints well separated from the protocol part.