MQTT-Finder: Provide HTTP API to get value from specified topic

[mschlenstedt]

Sometimes it is usefull to use one value from a MQTT topic in own scripts. This is quite complicated (connect, subscribe, get value, disconnect).

Use MQTT Finder to get a single value e.g. by curl:

http://loxberry/admin/system/mqtt-finder.cgi?gettopic=alexa2lox/Durchsage/lastTTSloxtime

These functions should also be available by the library LoxBerry::IO (Perl and PHP).