unified-storage: setup ring to shard requests (#103783)

* Updates the instrumentation_server service to use mux instead of the builtin router, and have it store the router in the module server: this is so we can register the /ring endpoint to check the status of the ring
* Create a new Ring service that depends on the instrumentation server and declares it as a dependency for the storage server
* Create standalone MemberlistKV service for Ring service to use
* Update the storage server Search and GetStats handler to distribute requests if applicable

pkg/storage/unified/client.go

@@ -158,7 +158,7 @@ func newClient(opts options.StorageOptions,
 		if err != nil {
 			return nil, err
 		}
-		server, err := sql.NewResourceServer(db, cfg, tracer, reg, authzc, searchOptions, storageMetrics, indexMetrics, features)
+		server, err := sql.NewResourceServer(db, cfg, tracer, reg, authzc, searchOptions, storageMetrics, indexMetrics, features, nil)
 		if err != nil {
 			return nil, err
 		}