M1: Define the scope and high level definitions #16

As a developer it is required a high level overview of the main features of the library and its scope by including:

• How Media Client Data will be loaded
• What CMCD validations are expected
• How CMCD validations results will be presented
• Additional features of the CMCD-validator, such as logs support, custom <key>:<values> validation
• Use cases - How it is expected to use the cmcd-validator from a user point of view.