Achievements - Update with some tests and admin endpoint

I wouldn't bring this anywhere the master branch right now but the tests I wrote are healthy and the admin endpoint is running smoothly. I squashed some commits together to make it prettier overall.

I _did_ fiddle in this branch beyond achievements, because I was working on the tests anyway. I made some `404`'s into `405`'s over at level components, level systems, files, what have you. I also added a decent `Allow` HTTP header (which was a TODO I bumpted into) which lets the client know what HTTP methods are allowed. Not really something we're going to use but it did allow for some juicy testing. So that's why I created `file.spec` and `languages.spec`. Dabbled in the `queue` endpoint as well but couldn't get the routing correct so I left those tests out for now (it wouldn't call the functions I thought it would).

Next PR should have some client-sided tests in it. The detours took longer than expected.
Too bad CreateJS isn't in the server, or we could just hook into all their Ease functions that TweenJS uses. I mean [look at these](https://github.com/CreateJS/TweenJS/blob/d74df450170f10913c69dfcc775af9ba97dccbd8/src/tweenjs/Ease.js#L99)