Several features for the node-boot persistence layer

[manusant]

Several improvements and features added to persistence layer along with samples for express applcation.

• Configuration as properties from app-config.yaml for the persistence layer
• Add support for custom query in Repositories
• Persistence Logger
• Migrations with '@migration' decorator
• Global and entity specific persistence event listener with @EntityEventSubscriber decorator (with service injection)
• Custom NamingStrategy for the persistence entities with @PersistenceNamingStrategy decorator
• Persistence Cache adapter using @PersistenceCache decorator