Create a drop-in file for mosquitto settings

[borpin]

EmonScripts/install/mosquitto.sh

Line 12 in e5b4e75

sudo sed -i "s/^persistence true/persistence false/" /etc/mosquitto/mosquitto.conf

As per most configurations, instead of editing a configuration file that may well be modified on upgrade, use drop in file of settings in the '/etc/mosquitto/conf.d` folder.

[borpin]

Enhancement of install, use drop-in instead of editing core file.