refactor(cli)!: move scaletest to exp/scaletest (#8339)

* refactor(cli): mv scaletest exp/scaletest

* make gen

cli/exp.go

@@ -0,0 +1,18 @@
+package cli
+
+import "github.com/coder/coder/cli/clibase"
+
+func (r *RootCmd) expCmd() *clibase.Cmd {
+	cmd := &clibase.Cmd{
+		Use:   "exp",
+		Short: "Internal commands for testing and experimentation. These are prone to breaking changes with no notice.",
+		Handler: func(i *clibase.Invocation) error {
+			return i.Command.HelpHandler(i)
+		},
+		Hidden: true,
+		Children: []*clibase.Cmd{
+			r.scaletestCmd(),
+		},
+	}
+	return cmd
+}