Fix URL fetch for BCO Published Objects

[syntheticgio]

Supports the call:

/<PREFIX>_<BCO_NAME>/<BCO VERSION>

Closes #37

[syntheticgio]

Working example: http://localhost:8000/BCO_000010/1.0 So the format /<BCO_NAME>/ works (does not specifically worry about the prefix, although may want to worry about that later depending on how we store these).

[syntheticgio]

I think this is ready to test @HadleyKing - looks to be working for me (if version is requested, going to follow up w/o version to get the most recent). I had played around with splitting the prefix from the bco name - but it seems like the bco name includes the prefix and so doesn't need to have it split out?

[syntheticgio]

Looks like we will need to do something more like http://localhost:8000/bcos/BCO_000010/1.0 @HadleyKing - it appears having a regex for the first item in the URL doesn't work unless there are things following it. Not sure if it is just django limitation or if there is something special you need to do; but prefixing the BCO ID fixes the issue. I'd propose:

http://localhost:8000/bcos/BCO_000010
http://localhost:8000/bcos/BCO_000010/1.0

As examples which get you the basic functionality.

EDIT: This might be wrong actually; I'm not sure why we keep getting the authentication issue with the first example above even with the bcos namespace added. Still looking into it.

EDIT2: Disregard, there was a conflicting URL endpoint for draft BCOs that was capturing the calls

[syntheticgio]

Ready for review @HadleyKing