Increase default length of auto generated passwords
    
    Installer/IPA generates passwords for warious purpose:
    * KRA
    * kerberos master key
    * NSSDB password
    * temporary passwords during installation
    
    Length of passwords should be increased to 22, ~128bits of entropy, to
    be safe nowadays.
    
    https://fedorahosted.org/freeipa/ticket/6116
    
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>