Persist OriginalRecord

This is a substantial rewrite of OriginalRecord to allow them to persist to LDP.

This isn't mergeable until the forthcoming Marmotta `3.3.0` release and a corresponding update to `marmottawrapper`.  Until then, I submit it for sanity check.
More potential thread safety issues.  Again, I'm not sure `Harvester` is effected, in the end, but we would want to be careful about concurrency.