validator: dont warn about optional parameters in MIME types like '; charset=UTF-8' which I suppose are valid for the POD schema
put the count of datasets into the validator output
validator: don't bother reporting a missing programCode if no bureauCode is set
add a non-standard _is_federal_dataset field to data.json, and set it to False on datasets that come from state catalog harvesters (see the code for how that's set), so our validator can skip the bureauCode check for datasets that we know are not from a federal catalog