Add loading context and loading bar component; integrate axios for API calls and update routing for locker registration

src/services/locker.service.js

@@ -0,0 +1,14 @@
+import api from './api';
+
+export const lockersService = {
+  registerLockers: async (cabinetId, lockers) => {
+    return api.post('/cabinet', {
+      cabinetId,
+      lockers: lockers.map(({ id, size, keyId }) => ({
+        id,
+        size,
+        keyId
+      }))
+    });
+  },
+};