Documentation overhaul for v1

[mantzas]

Is your feature request related to a problem? Please describe

Before we release v1 we need to overhaul our documentation.
This should be done when all issues for this milestone has been resolved.
We need to brainstorm on what is good documentation.
Should we rely on Go's documentation to provide details.
Should the readme have everything and we are ok with duplication?

Packages to cover:

• Documenting cache package #555
• Documenting client packages #556
• Documenting CLI #557
• Documenting AMQP #565
• Documenting gRPC #566
• Documenting HTTP component #567
• Documenting Kafka component #568
• Documenting SQS component #569
• Documenting correlation package #558
• Document encoding package #559
• Document errors package #560
• Document log package #561
• Document reliability package #562
• Document trace package #563
• Document root package #564