fix(nixos): use fixed startup timeouts

configs/nixos/modules/services/steamcmd.nix

@@ -65,13 +65,6 @@
       default = [ ];
       description = "TCP ports opened for the game service.";
     };
-
-    startupTimeout = lib.mkOption {
-      type = lib.types.str;
-      default = "15min";
-      example = "30min";
-      description = "Time systemd allows SteamCMD update and server startup to complete.";
-    };
   };
 
   config = lib.mkMerge [
@@ -145,7 +138,7 @@
               WorkingDirectory = "-${service.steamDir}";
               ExecStartPre = "+${prepareScript}";
               ExecStart = updateScript;
-              TimeoutStartSec = service.startupTimeout;
+              TimeoutStartSec = "15min";
             };
           };
 
@@ -169,7 +162,7 @@
               ];
               ExecStart = startScript;
               Restart = "on-failure";
-              TimeoutStartSec = service.startupTimeout;
+              TimeoutStartSec = "15min";
             };
           };
         };