Create amazon native API plugin

This issue would deal with the initial development of the native_api_amazon within the affiliates_connect_amazon sub-module by incorporating specifically by making API calls through Guzzle. Though initially, the API calls were supposed to be made by involving the REST API and creating REST resources for the same, however, making http calls through cURL for rest involves the need to call the curl_setopt() method to define the header and the particular HTTP verb like GET, POST, PUT, etc. and makes the job pretty complicated. However, Guzzle is far more flexible makes it relatively easier by just initializing the client and providing HTTP verbs and the URL. The authorization layer could be added later on. Also after the skeleton works fine we could add in REST UI integration into the parent module if needed.

As of now, it is done according to the following 2 steps:

• Setup Amazon Associate account for utilizing the resources of the Product Advertising API

• Create the basic working skeleton for the amazon native plugin by implementing dummy GET calls by using the Guzzle client to create required methods with HTTP calls to verify that the skeleton is correct and the data is being fetched. Also for the GET aTests could be added later on once the skeleton works as designed.