cache DiskInfo at storage layer for performance (#10586)

`mc admin info` on busy setups will not move HDD
heads unnecessarily for repeated calls, provides
a better responsiveness for the call overall.

Bonus change allow listTolerancePerSet be N-1
for good entries, to avoid skipping entries
for some reason one of the disk went offline.

cmd/storage-rest-client.go

@@ -161,6 +161,12 @@ func (client *storageRESTClient) Endpoint() Endpoint {
 }
 
 func (client *storageRESTClient) Healing() bool {
+	// This call should never be called over the network
+	// this function should always return 'false'
+	//
+	// To know if a remote disk is being healed
+	// perform DiskInfo() call which would return
+	// back the correct data if disk is being healed.
 	return false
 }