revert(api): decouple api from curriculum

This reverts commit c077ffe4b9
via PR #40703

api-server/server/boot/restApi.js

@@ -0,0 +1,5 @@
+module.exports = function mountRestApi(app) {
+  const restApi = app.loopback.rest();
+  const restApiRoot = app.get('restApiRoot');
+  app.use(restApiRoot, restApi);
+};