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/create-next-step.ts

@@ -0,0 +1,10 @@
+import { getLastStepFileContent } from './helpers/get-last-step-file-content';
+import { getProjectPath } from './helpers/get-project-path';
+import { reorderSteps, createStepFile } from './utils';
+
+const projectPath = getProjectPath();
+const { nextStepNum, challengeSeeds } = getLastStepFileContent();
+
+createStepFile({ stepNum: nextStepNum, projectPath, challengeSeeds });
+console.log(`Sucessfully added step #${nextStepNum}`);
+reorderSteps();