Manage password_validator regex

Manage password_validator regex

Horizon provides a password validation check, which OpenStack cloud
operators can use to enforce password complexity checks for users
within horizon.

A dictionary containing a regular expression can be used for
password validation with help text that is displayed if the password
does not pass validation.

HORIZON_CONFIG["password_validator"] = {
    "regex": '.*',
      "help_text": _("Your password does not meet the requirements."),

}

This change allows injection of the regex into horizons local_settings
file from a tripleo heat template

Change-Id: Ib6517c8f96148bea002b0e3442a26367b236928f
Depends-On: If82a80ed6a8e6e65aecc2a25ee6d60640ae03c9a
Closes-Bug: #1640800