This will be used both for async send for sensors and MQTT configuration
when the sensor will be async and each has its own thread (for example), we will know the pollrates for each based on their properties;
The MQTT subscriber will create the topics to subscribe to based on the properties of the sensors, as follows:
dev/hostname/temperature/pollrate; pollrate is taken from the properties of the sensors in sensor type class. When we'll add more properties which can be set on the fly, another topic will be created.
This will be used both for async send for sensors and MQTT configuration
Fix #31.