[Library Manager] Please Add AzureIoTHubMQTTClient to the Library Manager

[andriyadi]

Hi,

I've created an unofficial Azure IoT Hub client library for ESP8266, that's specifically built to leverage MQTT.

It's hosted at this Github repository: https://github.com/andriyadi/AzureIoTHubMQTTClient

Please kindly add it to Library Manager. Thanks!

[cmaglie]

Done!