This introduces ember-a11y-testing to acceptance tests via a helper
wrapper that allows us to globally ignore rules that we can address
separately. It also adds fixes for the aXe rules that were failing.
This includes fixes for newer template lint rules that came along with
updating that dependency, which was necessary to be able to use
the no-curly-component-invocation rule. It also updates some curly
invocations that I missed in #8075.