refactor: organise TypeScript config and migrate helpers (#44747)

* feat: allow more 1000 steps to be created at once

* refactor: start migrating to typescript

* refactor: delete-step to ts

* refactor: migrated some helpers

* refactor: migrate create-empty-steps

* refactor: migrate create-step-between

* refactor: finish migrating to TS

* refactor: migrate tests

* fix: ensure mock.restore is done after each test

* fix: prevent double-tscing

* fix: repair the tests

* chore: use ts-node for scripts

We don't need the performance boost of incremental compilation and
ts-node is easier to work with

* refactor: consolidate tsconfigs

* refactor: replace gulp

* fix: use ts-node for build-curriculum

* fix: allow ts compilation of config

* feat: create and use create:config script

* fix: add /config to eslint projects

* fix: remove gulp script

tools/challenge-helper-scripts/helpers/insert-erms.ts

@@ -0,0 +1,30 @@
+// Update given value with markers (labels)
+const insertErms = (seedCode: string, erms: number[]): string => {
+  if (!erms || erms.length <= 1) {
+    throw `erms should be provided`;
+  }
+
+  if (erms.length <= 1) {
+    throw `erms should contain 2 elements`;
+  }
+
+  const separator = '\n';
+  const lines = seedCode.split(separator);
+  const markerLabel = '--fcc-editable-region--';
+
+  // Generate a version of seed code with the erm markers
+  const newSeedCode = erms
+    .slice(0, 2)
+    .reduce((acc, erm) => {
+      if (Number.isInteger(erm)) {
+        acc.splice(erm, 0, markerLabel);
+      }
+
+      return acc;
+    }, lines)
+    .join(separator);
+
+  return newSeedCode;
+};
+
+export { insertErms };