add a partial template that returns an asset's URL and hash from webpack's manifest

still a mess but slightly more modular. also added a real 404 page.

assets/sass/abstracts/_responsive.scss

@@ -11,6 +11,7 @@
 @use "../pages/videos";
 @use "../pages/etc";
 @use "../pages/projects";
+@use "../pages/fourOhFour";
 
 // Responsive Awesomeness
 @media screen and (max-width: settings.$responsive-width) {
@@ -25,4 +26,5 @@
   @include videos.responsive();
   @include etc.responsive();
   @include projects.responsive();
+  @include fourOhFour.responsive();
 }