bugs.al.org -> GitLab redirect

Migration of Flyspray tasks to GitLab has started: archlinux-keyring#9 (closed)

We should add the relevant Nginx redirect logic sooner rather than later. Due to the amount of redirects (there is over 70k tasks), we can't do it the naive way, but should use a Nginx map.

https://stackoverflow.com/questions/29354142/nginx-how-to-mass-permanent-redirect-from-a-given-list/40576333

changed the description

mentioned in merge request !371 (closed)

mentioned in commit f3beea52

closed with commit 3b868260

closed with merge request !419 (merged)