Comment 2 for bug 1781971

MySQL uses the following pattern to achieve this use case:

mysql-server-core-5.7 ships binaries only with no configuration
mysql-server-5.7 depends on mysql-server-core-5.7 and provides management of /var/lib/mysql, supplies configuration in /etc/mysql (along with mysql-common) and provides system service definitions.

Perhaps nginx packaging could be adjusted to use a similar pattern (Andres' suggestion is equivalent; I'm just pointing out the pattern that already exists).