Preview: Mattermost command line tools

I linked this issue cli create doesn't send email but I think it has bearing on @cifvts design suggestion above.

Quoted from above:

"""
What I'd really love to see happen as a workflow is:

platform -create_user -team_name="myteam" -email="foo@bar.com" -generate_password

< system creates user, generates random password, expires password, sends password in confirmation email >
User logs in, puts in generated password, changes password, away they go.
"""

Thanks!