nixos/nextcloud: refactor database.createLocally

Fixes https://github.com/NixOS/nixpkgs/issues/228971

nixos/tests/nextcloud/with-postgresql-and-redis.nix

@@ -27,9 +27,6 @@ in {
         };
         config = {
           dbtype = "pgsql";
-          dbname = "nextcloud";
-          dbuser = "nextcloud";
-          dbhost = "/run/postgresql";
           inherit adminuser;
           adminpassFile = toString (pkgs.writeText "admin-pass-file" ''
             ${adminpass}
@@ -48,23 +45,6 @@ in {
 
       services.redis.servers."nextcloud".enable = true;
       services.redis.servers."nextcloud".port = 6379;
-
-      systemd.services.nextcloud-setup= {
-        requires = ["postgresql.service"];
-        after = [
-          "postgresql.service"
-        ];
-      };
-
-      services.postgresql = {
-        enable = true;
-        ensureDatabases = [ "nextcloud" ];
-        ensureUsers = [
-          { name = "nextcloud";
-            ensurePermissions."DATABASE nextcloud" = "ALL PRIVILEGES";
-          }
-        ];
-      };
     };
   };