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-empty-steps.ts

@@ -0,0 +1,38 @@
+import { getArgValues } from './helpers/get-arg-values';
+import { getExistingStepNums } from './helpers/get-existing-step-nums';
+import { getProjectPath } from './helpers/get-project-path';
+import { createStepFile, reorderSteps } from './utils';
+
+const anyStepExists = (steps: number[], stepsToFind: number[]) =>
+  stepsToFind.some(num => steps.includes(num));
+
+const projectPath = getProjectPath();
+const args = getArgValues(process.argv);
+
+const { num: numString, start: startString } = args;
+if (!startString) {
+  throw `No steps created. start arg val must be specified.`;
+}
+if (!numString) {
+  throw `No steps created. num arg val must be specified.`;
+}
+const num = parseInt(numString, 10);
+const stepStart = parseInt(startString, 10);
+
+if (num < 1 || num > 1000) {
+  throw `No steps created. arg 'num' must be between 1 and 1000 inclusive`;
+}
+
+const maxStepNum = stepStart + num - 1;
+
+const existingSteps = getExistingStepNums(projectPath);
+
+if (anyStepExists(existingSteps, [stepStart, maxStepNum])) {
+  throw `Step not created. At least one of the steps specified between ${startString} and ${maxStepNum} already exists.`;
+}
+
+for (let stepNum = stepStart; stepNum <= maxStepNum; stepNum++) {
+  createStepFile({ stepNum, projectPath });
+}
+console.log(`Sucessfully added ${numString} steps`);
+reorderSteps();