fixes#11723
- when deleting an invite/label/tag/webhook that doesn't
exist, Ghost would throw a 500 error
- this commit catches the NotFoundError
- also rejects from model if nothing was found
- spotted in Sentry
no issue
- Knex removed their use of several Bluebird methods, including `return`
- our code used `return`, but mostly to return null after a destroy action
- these uses have been replaced with `.then(() => null)` in order to
continue returning null and to avoid breaking anything
no issue
- webhooks UI requires the ability to edit webhooks
- added `edit` permission for `webhook`
- added `edit` method to v2 webhook controller
- added `PUT /webhooks/:id` route to v2 Admin API routes
