[DOCS] Add recommendation for EMQX (#1641)

* [DOCS] Add recommendation for EMQX

* [DOCS] Adjust the position and size of the sponsor logo

README.md

@@ -8,6 +8,10 @@
 
 OpenMQTTGateway project goal is to concentrate in one firmware different technologies and protocols, decreasing by the way the number of physical bridges needed, and hiding the different technologies singularity behind a simple & wide spread communication protocol; MQTT.
 
+## Sponsors
+
+<a href = "https://www.emqx.com/en?utm_source=github.com&utm_medium=referral&utm_campaign=OpenMQTTGateway-github-to-emqx-home"><img src="https://github.com/1technophile/OpenMQTTGateway/blob/development/docs/img/EMQ.png"  height="100"/></a>
+
 ## Documentation
 
 The documentation is [here](https://docs.openmqttgateway.com)

docs/prerequisites/broker.md

@@ -6,6 +6,7 @@ All the events or commands could pass by the broker.
 There are many choices of brokers, here are some of the most popular:
 * [Mosquitto](https://mosquitto.org/) (Open source)
 * [Moquette](https://moquette-io.github.io/moquette/) (Open source)
+* [EMQX](https://www.emqx.io/) (Open Source)
 * [HiveMQ](https://www.hivemq.com/hivemq/features/)
 * Embedded MQTT brokers (Home Assistant and OpenHAB)