Use a stub IndexRegistry when initialised in non-daemon mode

Offline processing of FQL logs for workload analysis or replay testing would benefit from being able to use C* as a library for parsing and preparation of the recorded CQL queries. One thing which makes this difficult is that preparing CQL statements involves validating any index restrictions via the IndexRegistry which means instantiating a ColumnFamilyStore, which has several side effects that are troublesome in an offline environment.

In the FQL processing use case this validation is unnecessary and I imagine this is true for most, if not all, offline tools. In these cases, we could use a stub IndexRegistry which enables validation to succeed, but which doesn't provide any real functionality.