Don't use contact_email address for default alert user

Instead ask for an email address
Also use this as a reason to add in some friendly option handling and
usage messages
Add in verbose option and some output for it
Create activist alert for all imported clinics

Refactor out the alert creation to a method and then use that to create
an alert for the activist user that we create.
Also unconfirm existing alerts and then reconfirm so if email addresses
change we stop sending them alerts