feat: Update swagger to openapi 3.0.4, update request payloads with examples (#11374)

swagger/definitions/resource/account_user.yml

@@ -0,0 +1,14 @@
+type: array
+description: 'Array of account users'
+items:
+  type: object
+  properties:
+    account_id:
+      type: integer
+      description: The ID of the account
+    user_id:
+      type: integer
+      description: The ID of the user
+    role:
+      type: string
+      description: whether user is an administrator or agent