KRACOEUS-7182:internal attachments

first shot at internal attachments.  
I feel like this URL should be built closer to the frontend. Like in the collection and or field definition. Is there any reason to not simply build it in the Uif-LinkField definition? Are any of these data elements not available as SpEL variables? I know this is similar to the way Rice does it, but the way they are doing it seems to have even worse issues in my mind.