Add option to not copy images and avoid content-based-uuid by default.

[Erotemic]

The way that images are ingested into the system is poorly designed. I believe that it forces a copy of the image into its internal database and generates a UUID based on the hash of the image. This is a lot of overhead and it is not necessary for many applications.

There should be an option to enable or disable this behavior. If the behavior is disabled it should use a random uuid.

I think some of the above might be in a partially-implemented state, but in any case we need to make it clear if image ingest is in "copy-mode" or "in-situ" mode (or maybe "lazy" mode?). Similarly, the uuid can just be a random one. If we want to do content based hashing, that is a good idea, but it has to be an option that defaults to off.

I don't think I have the bandwidth to implement this in the near future. Looking for someone who wants to help with it.