R1:36e0d080a789

Change `LiskDAO::generatePHID` to be `public`

Summary: Ref T6822. There are a bunch of places where we call `$something->generatePHID(...)` externally (outside of the class). Therefore, these methods need to be `public`.

Test Plan: I wouldn't expect //increasing// method visibility to break anything.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T6822

Differential Revision: https://secure.phabricator.com/D11363