KVClient new functionality

[benedekh]

• [ ] Cache meta-data of storage service. (Note: this meta-data might not be the most recent)
• [ ] Route requests to the storage node that coordinates the respective key-range
• [ ] There might be meta-data updates, initiated by the storage server if the library contacted a wrong node (i.e., the request could not be served by the currently connected node) due to stale meta-data
• [ ] Update meta-data and retry the request