* Add ability to specify pulse length in ZactuatorONOFF
Add an additional parameter to the MQTT message to control the actuatorONOFF pulse length e.g. `mosquitto_pub -t home/OpenMQTTGateway_MEGA/commands/MQTTtoONOFF -m '{"gpio":15,"cmd":"high_pulse","pulse_length":25}'`
* Simplify initialization of pulselength
* Initial generalization from a PWM LED controller, to a PWM controller.
Allow the config file to set the name of each channel and the number of channels.
Fade time is now per-channel, so MQTT messages can genuinely set an individual channel, and specify the fade time for that channel.
The default gamma is configurable in the config.
Rename set commands to config
correct json buffer size and gateway name
replace state to cmd
replace set by config
add restart and erase command
add unicity to gateway command switches
BLE devices shouldn't be child of the gateway
make the BTtoMQTT topic consistent with other definitions
