perf(languages): improved js caching of languages by using simplecache

fixes #7458

This replaces the ajax language views which booted the engine every view to only report a 304 not modified... this fix replaces this with just a few milliseconds and a normal cacheable .js file if you use tools like Varnish
no not true... you can still use it as you normally would as you can still pass `'language'`... the old cache urls also still work on this view