[DSpace 7 Upgrade] Bitstream provenance customization

[wwelling]

org.dspace.app.xmlui.cocoon.BitstreamReader

https://github.com/TAMULib/DSpace/pull/126/files#diff-19caf99684508b353cb1db1402f02b9c9d9f8f6477020beefc68d3f362b9dbd8

Purpose of this functionality is to add additional provenance metadata whenever a bitstream is added to an item by means of the legacy 6.x and prior REST API. The use case was when adding files with MAGPIE.

It may be better policy, however, not to add separate metadata values for each individual bitstream push. Furthermore, we will want to begin using the 7.x REST API sooner rather than later. Finally, MAGPIE is not utilizing this functionality for any customers in production at present. Let's put this one in the icebox for now.