Query source "individual" needs extra payload

SecurityCenter.query(source="individual") is useless because there is no way to specify the required payload {"scanID", "dateDirectory", "view"}.

The scan id can be found in scan_list.  The date directory seems to be the date the scan finished in the form "YYYY-mm-dd"; it is required but I have no idea why.  The only value for view I could find was "all", so that is hard-coded for now.

The attached commits add two new arguments to query: scan and directory, as well as documenting them.