Add Bridge Number field (#912)

data/fields/bridge/ref.json

@@ -0,0 +1,12 @@
+{
+    "key": "bridge:ref",
+    "type": "text",
+    "label": "Bridge Number",
+    "reference": {
+        "key": "bridge"
+    },
+    "prerequisiteTag": {
+        "key": "bridge",
+        "valueNot": "no"
+    }
+}

data/fields/ref_bridge_number.json

@@ -0,0 +1,5 @@
+{
+    "key": "ref",
+    "type": "text",
+    "label": "{bridge/ref}"
+}