the upstream project introduced a new Vue component "FormFooter", which
is used to end an input form, namely all settings forms. we should not
only use this component as well, but the save button on our forms
actually broke since the text dtuadmin.Save is replaced by base.Save.
also replace the use of dtuadmin.Seconds with base.Seconds, such that an
upstream change to dtuadmin.Seconds will not break the battery admin an
AC charger views.
