docs: Add documentation for integration APIs (#2300)

app/views/api/v1/models/_app.json.jbuilder

@@ -3,4 +3,8 @@ json.name resource.name
 json.description resource.description
 json.enabled resource.enabled?(@current_account)
 json.button resource.action
-json.hooks @current_account.hooks.where(app_id: resource.id)
+json.hooks do
+  json.array! @current_account.hooks.where(app_id: resource.id) do |hook|
+    json.partial! 'api/v1/models/hook.json.jbuilder', resource: hook
+  end
+end