refs https://github.com/TryGhost/Toolbox/issues/523 - This is a first pass media inliner going through all posts and checking to inline media from specified domains - As a working copy the inliner looks for image content from Revue and Substack
refs https://github.com/TryGhost/Toolbox/issues/524 - This is groundwork to contain logic related to external media scraping/inlining for posts.