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

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

@@ -0,0 +1,11 @@
+components:
+  parameters:
+    State:
+      name: state
+      in: query
+      required: false
+      description: |
+        Payment state filter. Accepts aliases like `accepted`, `settled`, `failed`
+        or canonical values like `orchestration_state_created`.
+      schema:
+        type: string