Roles permissions: separate cluster initialisation from db initialisation

Do the same as in QGEP, see https://github.com/QGEP/datamodel/pull/164

```sh
if [[ $roles ]]; then
  psql "service=${PGSERVICE}" -v ON_ERROR_STOP=1 -f ${DIR}/12_0_roles.sql
fi
if [[ $permissions ]]; then
  psql "service=${PGSERVICE}" -v ON_ERROR_STOP=1 -f ${DIR}/12_1_roles.sql
fi
```