[lyon] Add metrics info for PDU

data/grid5000/sites/lyon/pdus/wattmetre1.json

 {
   "ip": "172.16.63.8",
+  "metrics": [
+    {
+      "description": "Power consumption per outlet reported by wattmetre, in watt",
+      "name": "wattmetre_power_watt",
+      "optional_period": 20,
+      "period": 1000,
+      "source": {
+        "protocol": "wattmetre"
+      }
+    }
+  ],
   "model": "",
   "ports": {
     "0": "sagittaire-1",

data/grid5000/sites/lyon/pdus/wattmetre3.json

 {
   "ip": "172.16.63.8",
+  "metrics": [
+    {
+      "description": "Power consumption per outlet reported by wattmetre, in watt",
+      "name": "wattmetre_power_watt",
+      "optional_period": 20,
+      "period": 1000,
+      "source": {
+        "protocol": "wattmetre"
+      }
+    }
+  ],
   "model": "",
   "ports": {
     "0": "nova-1",

data/grid5000/sites/lyon/pdus/wattmetre4.json

 {
   "ip": "172.16.63.8",
+  "metrics": [
+    {
+      "description": "Power consumption per outlet reported by wattmetre, in watt",
+      "name": "wattmetre_power_watt",
+      "optional_period": 20,
+      "period": 1000,
+      "source": {
+        "protocol": "wattmetre"
+      }
+    }
+  ],
   "model": "",
   "ports": {
     "0": "taurus-1",

input/grid5000/sites/lyon/pdus.yaml

@@ -13,6 +13,14 @@ pdus:
             unit: W
             www:
               url: "http://wattmetre.lyon.grid5000.fr/GetWatts-json.php"
+    metrics:
+    - name: wattmetre_power_watt
+      description: Power consumption per outlet reported by wattmetre, in watt
+      period: 1000
+      optional_period: 20
+      source:
+        protocol: wattmetre
+
   wattmetre3:
     vendor: OmegaWatt
     model: ''
@@ -26,6 +34,14 @@ pdus:
             unit: W
             www:
               url: "http://wattmetre.lyon.grid5000.fr/GetWatts-json.php"
+    metrics:
+    - name: wattmetre_power_watt
+      description: Power consumption per outlet reported by wattmetre, in watt
+      period: 1000
+      optional_period: 20
+      source:
+        protocol: wattmetre
+
   wattmetre4:
     vendor: OmegaWatt
     model: ''
@@ -39,3 +55,10 @@ pdus:
             unit: W
             www:
               url: "http://wattmetre.lyon.grid5000.fr/GetWatts-json.php"
+    metrics:
+    - name: wattmetre_power_watt
+      description: Power consumption per outlet reported by wattmetre, in watt
+      period: 1000
+      optional_period: 20
+      source:
+        protocol: wattmetre