This enables the nodemcu to listen for multiple topics. First comes
the subsystem which is then followed by parameters for that specific
subsystem.
For 433MHz sockets this subsystem is called "rfsockets". It operates
on "rfsockets/<socket_name>/(status|switch)" wher it accepts and
reports with either "ON" or "OFF" as payloads. The subsystem therefore
complies with the Home Assistant mqtt component.
