Allow Attachments to Cascade to Master Features and Features

There are supporting docs that get attached to initiatives that are useful at every level of the product definition. Instead of re-attaching a document to a Master Feature or a Feature, it would be helpful to allow Initiative Attachments to be "applied" to Master Features and Features. This would avoid re-attachment, and also make version control easier so that all the changed docs would "cascade". Even if it were a link on the Master Feature or Feature, it would be super helpful