New IoT Central pricing plans

IoT Central has two new pricing plans designed to provide greater management, flexibility and simplicity for building IoT applications. This change allows you to: * Select a pricing plan based on application and message volume needs. * Change pricing tiers as needed. * Include two free devices per application. Learn more about [Azure IoT Central pricing](https://azure.microsoft.com/en-us/pricing/details/iot-central). * Azure IoT Central * Features * [ Azure IoT Central](https://azure.microsoft.com/en-gb/products/iot-central/)