nixos/treewide: Move rename.nix imports to their respective modules

A centralized list for these renames is not good because:
- It breaks disabledModules for modules that have a rename defined
- Adding/removing renames for a module means having to find them in the
central file
- Merge conflicts due to multiple people editing the central file

nixos/modules/services/networking/ddclient.nix

@@ -30,6 +30,14 @@ with lib;
 
 {
 
+  imports = [
+    (mkChangedOptionModule [ "services" "ddclient" "domain" ] [ "services" "ddclient" "domains" ]
+      (config:
+        let value = getAttrFromPath [ "services" "ddclient" "domain" ] config;
+        in if value != "" then [ value ] else []))
+    (mkRemovedOptionModule [ "services" "ddclient" "homeDir" ] "")
+  ];
+
   ###### interface
 
   options = {