GORA-535 Add a data store for Apache Ignite

This GSoC project aims to implement a new backend for Apache Gora, specifically the distributed database Apache Ignite. This proposal focuses on the native persistence of Ignite, which will be integrated in Gora as a new data store. The new backend implementation willl boost Apache Gora and open new use cases opportunities for its applications. Moreover, the approach of integration proposed will facilitate future implementations of other databases.