Update docs and remove unnecessary CI jobs

[acartmell]

• Updates the "Getting Started" page of the docs site to be a little clearer on how to import and use the library
• Updates the "Releasing" readme to be a little clearer on how releasing/publishing works
• Removes the test-visual-regression job from CircleCI: this is essentially a no-op, so no point wasting CircleCI resources on it
• Removes the publish-dsm job from CircleCI: I confirmed with Dana that we are no longer using Invision DSM
• Makes a trivial code change in the core package so that we can test that auto-publishing is working

[szujuiwu]

💯