Add configuration examples for various devices and functionalities

- Introduced multivent ventilation configuration for managing multiple zones.
- Added PID heating batteries configuration for temperature control.
- Created relay GPIO switch configuration for controlling relays.
- Implemented RGBW LED strip configuration for lighting control.
- Added Modbus CO2 sensor configuration for environmental monitoring.
- Introduced Sonoff S26 humidity controller example for humidity management.
- Created sprinkler irrigation configuration for garden management.
- Added thermostat on/off relay configuration for heating and cooling control.
- Implemented ventilation fan monitoring configuration for performance tracking.
- Added core concepts documentation for LightHub, detailing items, commands, and execution objects.

config-examples/modbus_ac_dimmer_legacy.json

@@ -0,0 +1,7 @@
+{
+  "mqtt": ["modbus-demo", "192.168.88.2"],
+  "items": {
+    "ac_dimmer": [4, [96, 0, 0, 255]],
+    "ac_dimmer_2": [4, [97, 0, 0, 255]]
+  }
+}