Generate dat file

Example file to write to /etc/openproject/installer.dat and then use via openproject configure:

postgres/retry retry
openproject/edition default
postgres/autoinstall reuse
postgres/db_host localhost
postgres/db_port 5432
postgres/db_username openproject
postgres/db_password POSTGRES_PASSWD
postgres/db_name openproject
server/autoinstall install
server/hostname DOMAIN_NAME
server/server_path_prefix
server/ssl yes
server/ssl_cert CERT_PATH
server/ssl_key KEY_PATH
server/ssl_ca
repositories/api-key RANDOM_STRING
repositories/svn-install skip
repositories/git-install skip
memcached/autoinstall install
openproject/admin_email EMAIL_ADDRESS
server/variant apache2