Use GPT Javascript implementation for Non-AMP

[pradeep910]

Since there will be latency issue when using AMP ads (library) on Non-AMP pages, we shall use default GPT implementation recommended by Google - https://developers.google.com/doubleclick-gpt/samples/display-test-ad

We already have some internal library that we can merge in this plugin and make changes to use -

1. GPT library for Non-AMP pages.
2. AMP ads for AMP Pages.

Goal will be to Code once & deliver on both AMP and Non-AMP pages.