Deactivate users when offboarded

Currently if a user is offboarded by their employer their emails simply bounce, and there is no way to deactivate their account. We have a property on the User table called "isLocked" that will prevent users from signing in if true, lets also make it prevent our systems from attempt to send email to those users. When the user is looked up by userId we should filter out any users with eq(User.isLocked, true). In fact, all listing and getting functions for users should filter out those with isLocked true so they do not show up in the UI anymore.