add recipe to unlock user accounts

This recipe is needed internally. We don't want to pull in dependencies to handle this which may require data bags or more, but instead keep it small and simple until the need arises to do otherwise.

This recipe is undocumented. Don't expose it to the user.

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
Merge pull request #31 from TelekomLabs/unlock

add recipe to unlock user accounts