Add qunit filter parameters to Ember CLI `/tests` route, and add UI (PR #14401)

This PR updates the qunit_skip_core, qunit_skip_plugins and qunit_single_plugin to be compatible with the Ember CLI /tests route. The public addModuleExcludeMatcher API is used for Ember CLI. The legacy require() solution is also maintained for the /qunit route.

This PR also amends the QUnit toolbar UI to hide unused options, and adds these new plugin-related parameters. These toolbar changes are compatible with both /tests and /qunit.

See commit messages for more information (to be rebased and merged)


Awesome! Let’s give it a try.