Add dedicated support for in-line caching.

[jxblum]

Currently, Apache Geode/Pivotal GemFire offers the JDBC Connector. However, this proves to be too limited in practice to be useful. Therefore, SBDG will offer dedicated support for inline caching that achieves 2 primary goals:

1. Support for any backend data store (e.g. RDBMS, Document, Graph, Key/Value, other) by integrating the Spring Data Repositories infrastructure.

2. Support for complex mapping. E.g. when using an RDBMS to back the cache for in-line caching, enable users to use Hibernate, or any other ORM tool (e.g. EclipseLink) to handle complex object hierarchies and relationships.

On top of these primary goals, this change will also include dedicated support configure in-line caching regardless of the context (e.g. Standalone vs. Cloud).

[jxblum]

This feature has already been coded as a proof-of-concept, here. The specific bits will come from this package.