Remove obsolete code reviews.

The datalog-demo review is committed and has been discussed and reviewed.

The domain-policy will be integrated into a later commit of the full fileproxy
functionality.
Add a code review for Datalog RPC.

This adds a code review for a set of commits that separate the datalog
code from the main code base and put it in its own process. The CloudProxy code
communicates with the datalog code across RPC over pipes.