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/get-step-template.test.ts

@@ -0,0 +1,57 @@
+import ObjectID from 'bson-objectid';
+import { getStepTemplate } from './get-step-template';
+
+// Note: evaluates at highlevel the process, but seedHeads and seedTails could
+// be tested if more specifics are needed.
+describe('getStepTemplate util', () => {
+  it('should be able to create a markdown', () => {
+    const baseOutput = `---
+id: 60d4ebe4801158d1abe1b18f
+title: Step 5
+challengeType: 0
+dashedName: step-5
+---
+
+# --description--
+
+step 5 instructions
+
+# --hints--
+
+Test 1
+
+\`\`\`js
+
+\`\`\`
+
+# --seed--
+
+## --seed-contents--
+
+\`\`\`html
+--fcc-editable-region--
+
+--fcc-editable-region--
+\`\`\`\n`;
+
+    const props = {
+      challengeId: new ObjectID('60d4ebe4801158d1abe1b18f'),
+      challengeSeeds: {
+        indexhtml: {
+          contents: '',
+          editableRegionBoundaries: [0, 2],
+          ext: 'html',
+          head: '',
+          id: '',
+          key: 'indexhtml',
+          name: 'index',
+          tail: ''
+        }
+      },
+      stepBetween: false,
+      stepNum: 5
+    };
+
+    expect(getStepTemplate(props)).toEqual(baseOutput);
+  });
+});