CDK-451: View isReady / signalReady

This PR builds on https://github.com/kite-sdk/kite/pull/98 and https://github.com/kite-sdk/kite/pull/99 adding support for isReady / signalReady on Views.
Yeah, I thought about that a little bit and you have a fair point.  The method is currently named in terms of what types of constraints the implementation supports converting to partition keys rather than what is theoretically possible.

How about instead I name it partitionKeyConversionSupported()?  Or can you suggest another name?