Migrate Project names to modular transactions

Summary: Also changes access modifiers on PhabricatorProjectTransactionEditor and sets up storage for applyExternalEffects.

Test Plan: Created new projects, attempted to create without name, with too long of a name, and with a name that conflicts with other projects and observed expected errors.

Reviewers: Blessed Reviewers, epriestley

Reviewed By: Blessed Reviewers, epriestley

Subscribers: epriestley

Maniphest Tasks: T12673

Differential Revision: https://secure.phabricator.com/D17947