hosts/carbon: Remove unused modules

hosts/carbon/configuration.nix

@@ -9,16 +9,12 @@
       ./ds-lite-ncfttb.nix
       ./mdns.nix
       ./net-dsl.nix
-      ./net-gastnetz.nix
       ./net-heimnetz.nix
       ./net-iot.nix
-      ./net-lte.nix
       ./net-mgmt.nix
       ./net-printer.nix
-      ./net-voip.nix
       ./ntp.nix
       ./ppp-ncfttb.nix
-      ./scan-to-gpg.nix
       ./wg-clerie.nix
     ];