refs #9942
* Added new middleware to trigger events
* Refactored webhooks service
- added new trigger service, moved listen service to its own file
- started listening to new site.changed event
- cleaned up trigger service to work with new webhook fields
- cleaned up tests
- removed redundant trigger method in v0.1 controller
no issue
Support for http://resthooks.org style webhooks that can be used with Zapier triggers. This can currently be used in two ways:
a) adding a webhook record to the DB manually
b) using the API with password auth and POSTing to /webhooks/ (this is private API so not documented)
⚠️ only _https_ URLs are supported in the webhook `target_url` field 🚨
- add `webhooks` table to store event names and target urls
- add `POST` and `DELETE` endpoints for `/webhooks/`
- configure `subscribers.added` and `subscribers.deleted` events to trigger registered webhooks