Add deprecation messages

[mpeyper]

redux-dynamic-reducer is no longer being used at IOOF in favour of redux-dynostore. As such, we should be telling people about this.

I think we should:

1. Add a message to the projects README
2. Write some migration docs, either in this repo or in the new one
3. Add a warning message to the packages if someone uses them
   • not sure if this is a minor or major version change? Probably major?
4. Deprecate the npm package
5. Archive this repo

Most features are covered by dynostore, but there are a few that aren't. I'm not sure if we want 1:1 feature parity before doing this.