Add MQTT Source

Identity 01
Broker 02
MQTT broker hostname or IP address, e.g. 192.168.1.100
Leave blank to keep the current password
Protocol 03
Unique MQTT client identifier. Change if running multiple instances.
Prefix for status and state topics, e.g. ledgrab/status
Publish homeassistant/.../config topics so MQTT-only Home Assistant installs get LedGrab automation + connectivity entities automatically.