SAK-21927 Add link to password reset from login tool.

This adds a link on the login page to either the password reset URL (if defined) or the password reset tool on the gateways site if it's present.

git-svn-id: https://source.sakaiproject.org/svn/login/trunk@132736 66ffb92e-73f9-0310-93c1-f5514f145a0a