Left over from: #10806

Now that: #11431 is merged, all extrinsics will have a transactional layer by default.

However, there may be situations you explicitly do not want a transactional layer, for example when you know that there is no need for it, or if you may even want to abuse this behavior(?)

We need to introduce a new attribute tag which can allow a user to note that an extrinsic should not have a storage layer, and then we skip adding the layer to the extrinsic.

This should be an easy task for anyone who is familiar with writing Rust macros.