Added queries and hits metrics for the Offloading Connector.
Also added timing metrics for store and load operations, which take the
average time it takes to load/store, per-token.
The metrics are available from Prometheus and from the StatLogger.
Signed-off-by: omerpaz95 <omerpaz95@gmail.com>
Co-authored-by: Omer Paz <Omer.Paz@ibm.com>