Add new "pin complex" type to supported keyguard PINs

This adds a feature to allow DevicePolicyAdmins to prevent using
simple PINs, which are defined as those containing more than 3
repeated values. Examples include '1234', '2468', '1111', '9876', etc.

Bug 12081139

Change-Id: I4ebe1c76a48087dcd7c878e9bd79a4e3ee2a27fe