Add Contributor information to the data model

[anjackson]

Can we get contributor info from PRONOM/LoC/FFW/COPTR/others? Add it to the model?

See also #6 (likely that will move to the Workbench)

[ross-spencer]

For Siegfried I had to roll my own SPARQL+Wikimedia tool called Wikiprov. It means folks can query the source of an identifier in Siegfried and see the last n- additions. The tool has a standalone app that can be built if you want to experiment. (Obs I mostly use it from the library, but has so far proven to be pretty stable).

• https://github.com/ross-spencer/wikiprov