Remove account migration capability when GPO IdP shuts down

[tcmitchell]

The account migration links and pages need to be taken down when the GPO IdP is turned off. This is anticipated in late June or early July 2017.

[tcmitchell]

See issue #1786 and pull request #1789 for details of the account migration implementation that has to be reversed in whole or in part.

[tcmitchell]

If we want an "in part" removal of this capability instead of "in whole", we can probably just remove the block of code that adds the transfer button to the profile page. The actual transfer page would then be accessible but unlinked in case we need to allow someone to migrate in the future, assuming the GPO IdP can be resuscitated to do its part of the transaction.