A "to deactivate" feature on inventory users

[Nebucatnetzer]

This way a technician could mark a user for deactivation and anyone could check
if there are users to deactivate. This would help if we would've to deactivate
a user at a certain date. The inventory tool could then show to all technicians
that the user needs to be deactivated. Then any technician could deactivate the
user and not just the technician responsible for the customer, increasing the
security of the customer.
Is related to the notification issue #28