fix(schema): add unique identifiers for VRF RouteTarget relationships

Add identifier and direction: outbound for import/export targets
in VRF and VRFDeviceAssignment to avoid bidirectional conflicts.

Ref: #41

schemas/vrf.yml

@@ -39,11 +39,15 @@ nodes:
         description: L3 VNI for symmetric IRB
       - name: import_targets
         peer: InfraRouteTarget
+        identifier: vrf_import_targets
         cardinality: many
+        direction: outbound
         optional: true
       - name: export_targets
         peer: InfraRouteTarget
+        identifier: vrf_export_targets
         cardinality: many
+        direction: outbound
         optional: true
       - name: interfaces
         peer: InfraInterface
@@ -99,11 +103,15 @@ nodes:
         kind: Parent
       - name: import_targets
         peer: InfraRouteTarget
+        identifier: vrf_assignment_import_targets
         cardinality: many
+        direction: outbound
         optional: true
         description: Device-specific import RTs
       - name: export_targets
         peer: InfraRouteTarget
+        identifier: vrf_assignment_export_targets
         cardinality: many
+        direction: outbound
         optional: true
         description: Device-specific export RTs