Summary:
Ref T10004. This restores "alice created this task." transactions, but in a generic way so we don't have to special case one of the other edits with an old `null` value.
In most cases, creating an object now shows only an "alice created this thing." transaction, unless nonempty defaults (usually, policy or spaces) were adjusted.
Test Plan: Created pastes, tasks, blogs, packages, and forms. Saw a single "alice created this thing." transaction.
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T10004
Differential Revision: https://secure.phabricator.com/D14820
5cb0de1efc