LPS-49784 Make it possible to be tested (rollback after review)

Hey @natecavanaugh 

This is the first draft of the image selector that should be used in blogs. The design is not the final one, since we're still waiting for the design team to get around everything to work on the blogs styling story.

Please, make sure to drop @sergiogonzalez last commit, which is for testing purposes only.

Let us know if you have any questions.

Thanks!