capture status

[carueda]

Similar to #10 for the "old" system, the task here is to capture a status attribute for every ontology version. As indicated in mmisw/mmiorr#279 a relevant reference is https://www.w3.org/2003/06/sw-vocab-status/note.html. Ideally we would use an existing status vocabulary, but, if nothing satisfactory is found, we could just go ahead and define our own.

@graybeal FYI and comments/suggestions.

[carueda]

I think I will just start working with http://www.w3.org/2003/06/sw-vocab-status/ns , the vocabulary discussed in the mentioned reference, which defines the following status values:

• unstable
  The meaning, deployment practices, documentation (or important associated software/services)
  associated with this term are liable to change arbitrarily at some point in the future.
  They may not, but stability is not guaranteed. Use with caution.
• testing
  The meaning, deployment practices, documentation and general understanding of this term are
  approaching some stability, but changes are still possible due to implementation experience
  or other unanticipated factors.
• stable
  The term is relatively stable, and its documentation and meaning are not expected to change substantially.
• archaic
  This term is marked as old-fashioned; although used, it is not considered typical of current best practice and alternative expressions may be preferable.

[carueda]

Note: The status attribute is an optional string in the ontology version model in the database, with not forced set of possible values. It's up to client applications to determine the acceptable values. See mmisw/orr-portal#13 .