Add a stub for a provenance-based PostgreSQL scan storage to the configuration

Configure both a provenance-based scan storage and a storage for provenance information in a PostgreSQL database. Remaining required configuration as per 1 needs to be injected e.g. via environment variables 2 like

export ort__scanner__storages__postgresStorage__connection__username=user export ort__scanner__storages__postgresStorage__connection__password=pass

export ort__scanner__provenanceStorage__postgresStorage__connection__username=user export ort__scanner__provenanceStorage__postgresStorage__connection__password=pass

The postgresStorage is set as the primary reader and writer. To benefit from any existing results, the fileBasedStorage is still added as a secondary reader, but new results are not being written to it anymore.