Bootstrap copied BFF and local accounts with public Sendico contracts (#34)

backend/contracts/sendico/api/parameters/payments_ref.yaml

@@ -0,0 +1,10 @@
+components:
+  parameters:
+    PaymentsRef:
+      name: payments_ref
+      in: path
+      required: true
+      description: Stable payment reference.
+      schema:
+        type: string
+        minLength: 1