v1.6.30 - Flow sensor consumed liters

New entity: Flow sensor consumed (Energy dashboard) — #30

Adds sensor.rainmachine_flow_sensor_consumed_liters, matching the official RainMachine integration's flow_sensor_consumed_liters.

• Value: flowSensorWateringClicks × 1000 ÷ flowSensorClicksPerCubicMeter (from provision.system)
• device_class: water, state_class: total_increasing, unit: L → usable directly as a water source in the HA Energy dashboard
• Disabled by default in the entity registry (only relevant with a flow meter installed) — enable it manually
• Extra attributes: clicks_per_cubic_meter, watering_clicks, leak_clicks, start_index

Thanks @sidsolutions-net for the request.