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

tsconfig.json

@@ -4,24 +4,8 @@
     "client/plugins/**/*",
     "client/src/**/*",
     "client/utils/**/*",
-    "tools/challenge-helper-scripts/**/*",
-    "config/certification-settings.ts",
-    "config/i18n/**/*"
+    "tools/challenge-helper-scripts/**/*.ts",
+    "tools/scripts/**/*.ts"
   ],
-  "compilerOptions": {
-    "lib": ["WebWorker", "DOM", "DOM.Iterable"],
-    "target": "es2020",
-    "module": "es2020",
-    "moduleResolution": "node",
-    "allowJs": true,
-    "jsx": "react",
-    "strict": true,
-    "esModuleInterop": true,
-    "experimentalDecorators": true,
-    "emitDecoratorMetadata": true,
-    "noEmit": true,
-    "resolveJsonModule": true,
-    "skipLibCheck": true,
-    "types": ["node", "jest", "@testing-library/jest-dom"]
-  }
+  "extends": "./tsconfig-base.json"
 }