feat: APIs for Integration Hooks (#2250)

- Introduces JSON Schema validations via JSONSchemer
- Add CRUD APIs for integration hooks

app/views/api/v1/accounts/integrations/apps/show.json.jbuilder

@@ -1,7 +1 @@
-json.id @app.id
-json.name @app.name
-json.logo @app.logo
-json.description @app.description
-json.fields @app.fields
-json.enabled @app.enabled?(@current_account)
-json.button @app.action
+json.partial! 'api/v1/models/app.json.jbuilder', resource: @app