Enable running all days at once

I'm kinda bored and wanted to.

src/main.cs

@@ -1,47 +1,36 @@
+using aoc2021;
+
 var arg = args.FirstOrDefault();
-switch (arg)
+if (arg == "all")
 {
-    case "1":
-        aoc2021.Day01.Go();
-        break;
+    var types = System.Reflection.Assembly
+             .GetExecutingAssembly()
+             .GetTypes()
+             .Where(t => t.IsSubclassOf(typeof(Day)) && !t.IsAbstract && t.Name != "DayTemplate")
+             .OrderBy(t => t.Name);
 
-    case "2":
-        aoc2021.Day02.Go();
-        break;
-
-    case "3":
-        aoc2021.Day03.Go();
-        break;
-
-    case "5":
-        aoc2021.Day05.Go();
-        break;
-
-    case "6":
-        aoc2021.Day06.Go();
-        break;
-
-    case "7":
-        aoc2021.Day07.Go();
-        break;
-
-    case "8":
-        aoc2021.Day08.Go();
-        break;
-
-    case "9":
-        aoc2021.Day09.Go();
-        break;
-
-    case "10":
-        aoc2021.Day10.Go();
-        break;
-
-    case "11":
-        aoc2021.Day11.Go();
-        break;
-
-    default:
-        aoc2021.Day12.Go();
-        break;
+    foreach (var type in types)
+    {
+        var day = (Day)Activator.CreateInstance(type)!;
+        day.Go();
+    }
+}
+else
+{
+    Day day = arg switch
+    {
+        "1" => new Day01(),
+        "2" => new Day02(),
+        "3" => new Day03(),
+        //"4" => new Day04(),
+        "5" => new Day05(),
+        "6" => new Day06(),
+        "7" => new Day07(),
+        "8" => new Day08(),
+        "9" => new Day09(),
+        "10" => new Day10(),
+        "11" => new Day11(),
+        _ => new Day12(),
+    };
+    day.Go();
 }