Rename tu-bylaws.aur.a.o to package-maintainer-bylaws.aur.a.o

The role has been renamed[1], so rename the bylaw subdomain.

tu-bylaws.aur.a.o will be kept around for some time redirecting to
package-maintainer-bylaws.aur.a.o.

[1] archlinux/rfcs!7

Ref #533