High-level acceptance tests shouldn't expose low-level concepts such as
the Resource Loader ("RL"). Merge the "And the RL module has loaded"
step into the "Given I am on the test page" step as they are only ever
used together.
Changes:
* Use the ArticlePage#wait_until_rl_module_ready helper method provided
by mediawiki_selenium@1.7.3.
* Update and include the Gemfile.lock.
Change-Id: Ic81eae5dc0caa8ec51c91b21aef544f52d8c49e1
