R13: DMaaP and Kafka updates

See https://wiki.onap.org/display/DW/Deprecation+and+Removal+of+DMaaP+Message+Router

Background

The Policy Framework uses DMaaP as its asynchronous messaging protocol. A common utility library is used to provide DMaaP as a communication mechanism to the rest of the Policy Framework components.

Purpose

There is an activity in ONAP to upgrade the DMaaP Message Router component,

Scope

• Update the DMaaP client in the Policy Framework common utility library.
• Check that all asynchronous messaging continues to work

Background

The Policy Framework uses DMaaP as its asynchronous messaging protocol. A common utility library is used to provide DMaaP as a communication mechanism to the rest of the Policy Framework components.

Purpose

The purpose is to add a direct Kafka client to the Policy Framework common utility library. This would allow Kafka messaging to be selected as an asynchronous messaging protocol for the Policy Framework. 

Scope

• Add a Kafka client in the Policy Framework common utility library.
• Configure the Policy Framework components to use Kafka instead of DMaaP
• Check that all asynchronous messaging continues to work