CT Linkwarden Postgresq: Debian 13 fixes

linkwarden: removed unnecessary build step, fixed deploy command
postgresql: locked major version, bumpt it from 17 to 18, updated config for compatibility, added sleep to config to make sure Postgres is up
aptcacherng: skips overwriting existing service symlink

CT-Files/postgresql/Configs/pgadmin-user-preferences.json

@@ -1,6 +1,6 @@
 {
     "preferences":
         {
-            "misc:themes:theme": "system"
+            "misc:user_interface:theme": "system"
         }
 }