Create basic file structure for Arc4 implementation

Chaos/Cipher/Arc4.hpp

@@ -0,0 +1,9 @@
+#ifndef CHAOS_CIPHER_ARC4_HPP
+#define CHAOS_CIPHER_ARC4_HPP
+
+namespace Chaos::Cipher::Arc4
+{
+
+} // namespace Chaos::Cipher::Arc4
+
+#endif