Now that the outgoing node-webhooks are implemented we should also
document them, so developers can start building on top of them.
[ ] Write an example in the Tutorials section on how to use webhooks
[ ] Create an overview over the various webhook mechanisms we intend to offer:
outgoing node webhooks
outgoing app webhooks (through the GDC, allows developers to register or deregister an app-wide webhook called for any node from its installation base)
incoming webhooks (LSPs and others telling us we should wake up
Now that the outgoing node-webhooks are implemented we should also document them, so developers can start building on top of them.