Cache component interface.

Providing a high level of adaptability, Shark's kernel will relay on this component implementation for caching of runtime objects (currently the processes and resources), so that execution can be performed much faster. If this component isn't present, kernel will not perform any caching - it will always ask for data from DB. If shark is used from more then one VM on the same DB at the same time, it must be configured not to use any implementation of this component.