Support PhabricatorOpaqueEnvelope for managing database passwords
Summary: Currently, MySQL/MySQLi connections store passwords in plain text on the object. Allow them to be stored in PhutilOpaqueEnvelopes instead. See D3053.
Test Plan: Loaded site.
Reviewers: vrana, btrahan
Reviewed By: vrana
CC: aran
Differential Revision: https://secure.phabricator.com/D3054