Behat: Expand test for new background steps

[Rebecca Blundell]

There is a test currently called /user_content/test.feature, which could be expanded to better test the background steps functionality. Currently it creates content using the background steps, and visits the created pages, but doesn't confirm the created content exists on the pages.

1. We should re-name the test to be more descriptive of its functionality - test_background_steps.feature would work.

2. Confirm that all the background steps are tested in this test.

3. Check that the content added in the background is displayed correctly on the page.