Support cascading "beacons" to fire websockets/webhooks

[andyslack]

There is a functionality gap with Triggers/Stored Procedures etc whereby updates are made within the database instance and do not trigger webhooks/websocket updates.

One solution could be to host a "_llana_beacon" table which triggers "child" updates based on a "parent" table update.

E.g. If "SalesOrder" is updated, then fire updates for relations in "Customer" table.

Table schema:

parent	child	on_create	on_update	on_delete
SalesOrder	Customer	true	true	true

In the relevant controllers, the lookup based on parent, call webhook/websocket on child table.