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/monitoring/zabbix-server.nix

@@ -44,6 +44,11 @@ let
 in
 
 {
+  imports = [
+    (lib.mkRenamedOptionModule [ "services" "zabbixServer" "dbServer" ] [ "services" "zabbixServer" "database" "host" ])
+    (lib.mkRemovedOptionModule [ "services" "zabbixServer" "dbPassword" ] "Use services.zabbixServer.database.passwordFile instead.")
+  ];
+
   # interface
 
   options = {