Exim4: Copy all outgoing mail - split file config

Adapted from flat-file config at Raymii.Org.

/etc/exim4/main/20_exim4_prionyx_system_filter
system_filter = /etc/exim4/system_filter.exim
system_filter_directory_transport = local_copy_outgoing

/etc/exim4/transport/40_exim4_prionyx_system_filter
local_copy_outgoing:
  driver = appendfile
  delivery_date_add
  envelope_to_add
  return_path_add
  group = Debian-exim
  user = Debian-exim
  mode = 0660
  maildir_format = true
  create_directory = true

/etc/exim4/system_filter.exim
if $sender_address_domain is waspa.org.za
then
unseen save /var/mail/waspa.org.za/archive/.${tr{$sender_address}{.}{_}}.outgoing/
endif

exim -bV

service exim4 reload