Fix
[#web](https://github.com/orgs/twentyhq/projects/1/views/3?pane=issue&itemId=75329194)
This PR does 2 things:
- migrate webhooks to TwentyORM
- Fix inversion between objectNameSingular and operation in webhook
eventName. It is stored as {objectNameSingular}.{operation} and we were
querying {operation}.{objectNameSingular}