config: Add invenio.preservationmeter to packages

Signed-off-by: Joao Goncalves <jsvgoncalves@gmail.com>
preservationmeter: Starting tests

* Adds record mocking to tests
* API now gets list of files using get_record(recid)

Signed-off-by: Joao Goncalves <jsvgoncalves@gmail.com>