Add wasm example for discount function

Author: devisscher

discounts/wasm/discount/default/generate_cart_run.graphql.liquid

@@ -0,0 +1,15 @@
+query Input {
+  cart {
+    lines {
+      id
+      cost {
+        subtotalAmount {
+          amount
+        }
+      }
+    }
+  }
+  discount {
+    discountClasses
+  }
+}

discounts/wasm/discount/default/generate_delivery_run.graphql.liquid

@@ -0,0 +1,10 @@
+query Input {
+  cart {
+    deliveryGroups {
+      id
+    }
+  }
+  discount {
+    discountClasses
+  }
+}

discounts/wasm/discount/default/locales/en.default.json.liquid

@@ -0,0 +1,4 @@
+{
+  "name": "{{name}}",
+  "description": "{{name}}"
+}