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

curriculum/lint-localized.js

@@ -0,0 +1,8 @@
+var glob = require('glob');
+const lint = require('../tools/scripts/lint');
+const { testedLang } = require('./utils');
+
+glob(`challenges/${testedLang()}/**/*.md`, (err, files) => {
+  if (!files.length) throw Error('No files found');
+  files.forEach(file => lint({ path: file }));
+});