Comment 5 for bug 1657187

At this stage, we will grow 'juju change-user-password' command to acquire a --reset flag. If controller admins run the command in this form, the user whom they request a password change for, will have password reset and a new registration string will be issued. This can be run against any active user.

Initial, state layer part of this work is proposed against develop: https://github.com/juju/juju/pull/7740

There will be other means to obtain registration key for the controller to be re-used on multiple client, to address bug # 1657652. 'juju register' command will be updated at the same time.