As decision making quite often requires access to more than one slave entry,
it's better to keep the logic above configuration generation. Also
configuration generation is already complex, and it's better to have it
simplified, especially in case of switching the component.

Use already prepared values from apache-custom-slave-list.cfg.in in
default-virtualhost.conf.in to simplify even more.

Pass variables to the other profiles without casting them to string, so that
they work out of the box.