Export as CSV doesn't include publication date, link to Federal Register

[alexkreidler]

The CSV header for the search.csv response includes these categories

agency_names,action,summary,dates,addresses,further_info,supplementary_info,system_name,system_number,security,location,manager,authority,purpose,categories_of_individuals,categories_of_record,source,routine_uses,storage,retrieval,retention,safeguards,access,contesting,notification,exemptions,history

It doesn't include the date the notice was published or the link to the Federal Register source, which is critical for unambiguously identifying the SORN and for users who want to verify the data with or read the original notice.

The best alternative I have found is using the Federal Register's search system to search for the system_name which contains the system number, like this:
https://www.federalregister.gov/documents/search?conditions%5Bterm%5D=Mass+Alert+and+Notification+Systems+%28MANS%29%2C+EPA-44.#

However, as you can see from that example, the same system often has multiple notices for revisions, etc, so there is no guarantee the first response is the associated SORN.

It would be great to include at least those two fields, possibly citation and document_number, which is used to uniquely identify notices in the Federal Register API, and perhaps other fields from the Federal Register ruby model:

all_sorns/app/models/federal_register_client.rb

Lines 9 to 11 in d62d2ba

	@fields = fields || ["action", "agencies", "citation",
	"dates", "full_text_xml_url", "html_url",
	"publication_date", "title", "type"]

I'd be happy to work on a PR for this if you would be open to that!