Add SAJ H1 grid meter (power and energy)

Be aware that the power is coming from the additional smart meter that should be installed together with the inverter.
Without the smart meter, the readings won't be correct or 0.

templates/definition/meter/saj-h1.yaml

@@ -5,13 +5,30 @@ products:
       generic: H1 Series Hybrid Solar Inverter
 params:
   - name: usage
-    choice: ["pv", "battery"]
+    choice: ["grid", "pv", "battery"]
   - name: modbus
     choice: ["tcpip"]
   - name: capacity
     advanced: true
 render: |
   type: custom
+  {{- if eq .usage "grid" }}
+  power:
+    source: modbus
+    {{- include "modbus" . | indent 2 }}
+    register:
+      address: 0x40A1 # SmartMeterTotalGridPowerWatt (undocumented)
+      type: holding
+      decode: int16
+  energy:
+    source: modbus
+    {{- include "modbus" . | indent 2 }}
+    register:
+      address: 0x40FD # Total_FeedInEnergy
+      type: holding
+      decode: uint32
+    scale: 0.01
+  {{- end }}
   {{- if eq .usage "pv" }}
   power:
     source: modbus