Refactor Caido::Instance class initialization and add example_helper method

Author: hahwul

lib/caido/helpers/_example.rb

@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module Caido
+  # Instance class
+  class Instance
+    def example_helper
+      'test'
+    end
+  end
+end