Move a bunch of scripts and CSS to assets so they can be processed with Hugo Pipes

Use Pipes to fingerprint and add SLI information to <script> and <link> tags.

assets/scripts/sketch-utils.js

@@ -0,0 +1,7 @@
+function getInlineSketchWidth() {
+    return getComputedStyle(document.documentElement).getPropertyValue("--body-width");
+}
+
+function convertRemToPx(rem) {
+    return rem * parseFloat(getComputedStyle(document.documentElement).fontSize);
+}