roles/postgresql-server: Deploy PostgreSQL

The *postgresql-server* role installs and configures PostgreSQL on
Fedora/RHEL-based distributions.

roles/postgresql-server/templates/postgresql-setup.service.j2

@@ -0,0 +1,11 @@
+[Unit]
+Before=postgresql.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=true
+Environment=PGDATA={{ pgdata_dir }}
+Environment=LANG={{ pg_locale }}
+User=postgres
+Group=postgres
+ExecStart=/bin/sh -c "[ -f ${PGDATA}/PG_VERSION ] || initdb -D ${PGDATA}"