The new merged app-crypt/certbot has blockers on all the old split
modules like certbot-nginx, which leads to poor UX when users who have
e.g. certbot-nginx in their world file now to try to upgrade.
Add a dummy set of ebuilds for the old split modules to depend on the
merged certbot with the right USE, which we can last-rite in a while.
Signed-off-by: Thibaud CANALE <thican@thican.net>