Allow attachments field type to be used on custom field associations

Presently all attachments fall into a single attachment bucket. It would be more useful if these attachments could be related to a custom field so that they could be properly organized in the field / screen layout.

For example, Description Attachments would be used to describe the problem, possibly w/ screenshots. Other attachments such as Design/Analysis attachments, Test Steps attachments, and Test Result attachments would all be useful attachment fields. Having these as custom fields, users can more easily hide and show the relevant attachments for the proper audience on the separate screens/tabs. Right now although the screen/tab configuration helps do this with normal fields, all of the attachments appear in one location only.

The benefit is that supporting this in the native custom fields, users can more easily customize their existing fields. I understand the attachment types are already extendible but this would be a good case where the native attachment function should be available for the custom fields-- without using an unsupported 3rd party component.