Autogenerate known colors and palettes

This will make it a bit easier to make changes

eng/Generator/Program.cs

@@ -0,0 +1,19 @@
+using Generator.Commands;
+using Spectre.Cli;
+
+namespace Generator
+{
+    public static class Program
+    {
+        public static int Main(string[] args)
+        {
+            var app = new CommandApp();
+            app.Configure(config =>
+            {
+                config.AddCommand<ColorGeneratorCommand>("colors");
+            });
+
+            return app.Run(args);
+        }
+    }
+}