* The creation of a testing div is specific to Rails, so that is
moved back out of setupTests();
* We've removed the `Discourse` globals from the acceptance helpers in favor of
`setApplication`/`getApplication`.
* We pass the container to setupTests because there is no
`__container__` in later Ember versions.
* `App` is now `app` because it's not a constant or class, it's an
instance of an application.
I also took the opportunity with this commit to move some test specific
stuff out of `discourse-loader` which is loaded on the front end of the
application. The test module building now happens in the `test_helper`
bundle.
This is long overdue. We had a lot of (not linted) code to initialize
our test suite as part of the Ruby `test_helper.js` bundle.
This refactor moves that out to a `setup-tests` module, which imports
all the modules properly, rather than using `require`.
It also removes the global `server` variable which some tests were using
for pretender. Those tests are fixed, and in the case of widget tests,
support for a `pretend()` was added, which mimics our acceptance tests.
One problematic test was removed, which overwrites `/posts` - this could
break tons of other tests depending on order.
