Proposal: Initial namespaces proposal

This is based on feedback and discussion that came out of #1017 

There was discussion that the term project may be problematic, so have removed it in favor of namespace.

I think this aligns nicely with the ACL model discussed thus far.

Feedback appreciated.

@erictune @lavalamp @smarterclayton 


I still think the namespace ought to go first. If that makes it hard to do an etcd list, then so be it. Is that even an allowed usecase? Namespaces are supposed to segment the cluster, no?