App UI update

Today we released a major UI change of the Rush App:
- Now app opens in standalone mode rather been embedded inside the Shopify window, giving more space to present information
- The tracking page is accessible from the left menu, making it easy to access and find
- Shipments are not open in the new tab, but in the same windows, and can be paginated via the navigation
- Language picked is moved in the top menu for easy access.
Improvements:
- Faster page load times
- Multiple bug fixes and improvements.