Add links to authors of add-ons in blocklist submission page

[diox]

Fixes mozilla/addons#16019

Description

This adds a global link to all authors of add-ons in a block submission add/change page, and individual link for each add-on being blocked on that same page.

Screenshot

[eviljeff]

I'm kind of interested how much this blows up the query count... (but don't want to know how back the query count already is for these pages...)

[diox]

I used the attach_all_authors transformer to avoid blowing up the query count (only one extra query to fetch all the UserProfiles), and checked using Django Debug Toolbar, but forgot to add an automated test, I'll do that.