add history to edit_host
    
    Hosts now have history.
    
    host table was split to host (containing ephemereal and non-editable
    data (load, activity, name, user_id)) and host_config containing
    data changeable by admins (archs, capacity, ...). This table is
    versioned and searchable via queryHistory.
    
    Fixes: https://pagure.io/koji/issue/638