add support for tuning healing to make healing more aggressive (#11003)

supports `mc admin config set <alias> heal sleep=100ms` to
enable more aggressive healing under certain times.

also optimize some areas that were doing extra checks than
necessary when bitrotscan was enabled, avoid double sleeps
make healing more predictable.

fixes #10497

cmd/global-heal.go

@@ -186,7 +186,10 @@ func deepHealObject(bucket, object, versionID string) {
 			bucket:    bucket,
 			object:    object,
 			versionID: versionID,
-			opts:      &madmin.HealOpts{ScanMode: madmin.HealDeepScan},
+			opts: &madmin.HealOpts{
+				Remove:   true, // if found dangling purge it.
+				ScanMode: madmin.HealDeepScan,
+			},
 		}
 	}
 }