FIX This link breaks when get params are added to report URLs

This fixes a conflict where GET params are automatically added to the URL and ID is put in the wrong place. 

Example:
Before: http://localhost:8080/admin/pages/edit/show?locale=en_NZ/11834
After: http://localhost:8080/admin/pages/edit/show/11834?locale=en_NZ

ps. This is generating a template - $ID isn't actually being rendered yet which is why its in single quotes.
Hm, I'm not sure how well `Controller::join_links` will handle placeholder values. It'd be easier to change formatting into a callback (takes the field value and item as parameters), instead of a template string.