[DOC] Create standalone content for the Kafka Bridge

WHAT
The Kafka Bridge documentation is currently included with the Configuring guide.
It should be a separate bridge doc

HOW

• Separate the Kafka Kafka Bridge chapter from the Configuring guide. 
• Move/amalgamate the deploying section into the Deploying guide  DONE
• Migrate the Producing and consuming content and API reference as Bridge doc in bridge repo upstream DONE
• Edit the content so that it is common to rhel and ocp
• Sync the restructured content downstream
• Create downstream common doc that sits as common doc on splash page (applicable to OCP and RHEL)

DONE
Using the Kafka Bridge guide (on bridge repo)
API reference (on bridge repo)
Using the Kafka Bridge (downstream)