♻️ Refactor bundle mechanism

Mainly leave shadow-cljs for build cljs stuff and use esbuild
for bundle all js dependencies, completly avoiding all possible
incompatibility issues between js libraries and google closure
compiler.

frontend/vendor/hljs/index.js

@@ -0,0 +1,5 @@
+import h from "highlight.js";
+
+export function highlightElement(node) {
+  return h.highlightElement(node);
+}