Confirm on inactivating group member

[triszt4n]

Required functionality

A confirmal window for the inactivation button (see inactivate_user_button(group) method above) so that we don't accidentally inactivate members

Example here:

pek-next/app/decorators/group_member_decorator.rb

Line 70 in b1504f4

data: { confirm: "Biztos, hogy archiválni szeretnéd #{user.full_name}-t?" }