chore(graphql): add v2 schema and query files

Author: suchapalaver

crates/query/graphql/horizon_detection.query.graphql

@@ -0,0 +1,8 @@
+# Query to detect if Horizon (V2) contracts are active in the network
+# This query checks for the existence of PaymentsEscrow accounts which indicate V2 is active
+
+query HorizonDetectionQuery {
+    paymentsEscrowAccounts(first: 1) {
+        id
+    }
+}

crates/query/graphql/latest_ravs_v2.query.graphql

@@ -0,0 +1,19 @@
+query LatestRavs(
+    $payer: ID!
+    $dataService: ID!
+    $serviceProvider: ID!
+    $collectionIds: [ID!]!
+) {
+    latestRavs(
+        where: {
+            payer: $payer
+            dataService: $dataService
+            serviceProvider: $serviceProvider
+            id_in: $collectionIds
+        }
+    ) {
+        id
+        valueAggregate
+        timestamp
+    }
+}