prepare DRAFT message response metadata for RuffGuide responses

[jdeck88]

From John Kunze's proposed RuffGuide messaging system for counting heirarchical identifiers:

Abstract:
RuffGUIDe is a convention for asserting a rough number and optional list of identifiers associated with a given set of objects. It is similar to a sitemap extended to general identifiers (not just URLs) plus a required identifier count, but where the identifier list is optional.

Response:
To participate in RuffGUIDe for a given set or subset of identifiers, it is sufficient to generate a small plain text "message" encoded in [YAML] or [JSON]. The message could, for example, be stored in a web-exposed file similar to a robots.txt file and updated as (in)frequently as desired, or it could be returned in response to an API query. Either way there must be a URL, known as a "RuffGUIDe entry point", that returns the message.

Structurally, a RuffGUIDe "message" is a serialization, in YAML or JSON, of one or more metadata blocks.

space: (sub)namespace, eg, ark:/12345 or ark:/12345/sb9
member_count: integer
date_counted: yyyy-mm-dd
member_list: (optional) URL-to-sitemap
note: (optional) free text

[jdeck88]

May want to add resourceType to response.... To clarify, this would be a service that would respond to any Geome identifier to get information on numbers of objects referenced by that identifier.... this should be very similar to existing services....