Adds functionality to search images from post page and attach as featured image.
You will require to create an API key on bing for search API.
GOTO: https://azure.microsoft.com/en-us/services/cognitive-services/bing-image-search-api/ or https://dev.cognitive.microsoft.com/docs/services/56b43f0ccf5ff8098cef3808/operations/571fab09dbe2d933e891028f
And generate your “Ocp-Apim-Subscription-Key”