Write theme JSON files from buildThemes script

Co-Authored-By: Nate Butler <1714999+iamnbutler@users.noreply.github.com>

styles/utils/decamelizeTree.ts

@@ -0,0 +1,21 @@
+import { snakeCase } from "case-anything";
+
+export default function decamelizeTree(object: { [key: string]: any }) {
+  const snakeObject: { [key: string]: any } = {};
+  for (const key in object) {
+    snakeObject[snakeCase(key)] = decamelizeValue(object[key]);
+  }
+  return snakeObject;
+}
+
+function decamelizeValue(value: any): any {
+  if (typeof value === "object") {
+    if (Array.isArray(value)) {
+      return value.map(decamelizeValue);
+    } else {
+      return decamelizeTree(value);
+    }
+  } else {
+    return value;
+  }
+}