getContentFromHub should overwrite most properties with their value from the item.

[mjuniper]

When I initially did #499, @tomwayson said:

I think we should add more overrides here.
...
Honestly, I think it'd be better to use a block list based on known oddities (name, extent, etc) than an allow list.

I did not do follow his advice at the time because it seemed less risky to scope it to things I knew I needed. And also because mergeObjects takes a whitelist. But I have come around to his way of thinking. We should switch to using a blacklist and overwrite most properties with their values from the item.