DATAMONGO-779 : Adding the Mongo JNDI factory class to create MongoTemplate through JNDI

This is new class supporting the feature Mongo JNDI factory class to create MongoTemplate through JNDI in J2EE Application Server.

This Factory class creates the MongoTemplate whenever the org.springframework.jndi.JndiObjectFactoryBean  requests for loading the JNDI MongoDB object.