Trigger all "Firehose" webhooks on all transactional edits

Summary: Depends on D19047. Ref T11330. Triggers every firehose hook on every edit; prepares for Herald triggers.

Test Plan: Configured a firehose hook, edited some objects, saw callbacks.

Maniphest Tasks: T11330

Differential Revision: https://secure.phabricator.com/D19048