Generalized mechanism for data provenance

[awalter17]

There should be an interface Sourced with API getSource(), that returns a descriptor of all data objects involved in the creation of the Object in question. Intuitively, Module is a good candidate for this descriptor. But we must be very careful about weak versus strong references.

We want a provenance post processor which, for each output that implements this interface, attaches all inputs via setSource(...).

This allows images to know how were they were generated and even reproduce that workflow again in some cases. ImageJ-OMERO would use this to know which OMERO datasets are relevant to newly created images. But the applications are numerous and varied.

[awalter17]

See also the Identifiable interface which would let us keep "weak references" to otherwise expensive objects in the provenance history.