Prepare update to Spring Data Codd GA.

NOTE: Do not merge. This PR is intended to already contain a few minor upgrades needed to the Spring Data APIs that will ship with the Codd GA release. I'll update the PR after the release accordingly.

Adapted auto-configuration code to use the new constructor introduced 
in Spring Data Commons' AnnotationConfigurationSource.

Added snapshot repository to be able to refer to the Spring Data snapshots until Codd GA is released.