go reactive: add dependency callback
go reactive: add dependency callback

We want to move binlog invalidation out of sqlgen/livesql.
By adding a hook in AddDependency, we can add a child
resource in the computation node that caches SQL result,
and kick off custom invalidations.

samsarahq/thunder,samsarahq/thunder,samsarahq/thunder,samsarahq/thunder,samsarahq/thunder