ListObjects Metadata Caching (#10648)

Design: https://gist.github.com/klauspost/025c09b48ed4a1293c917cecfabdf21c

Gist of improvements:

* Cross-server caching and listing will use the same data across servers and requests.
* Lists can be arbitrarily resumed at a constant speed.
* Metadata for all files scanned is stored for streaming retrieval.
* The existing bloom filters controlled by the crawler is used for validating caches.
* Concurrent requests for the same data (or parts of it) will not spawn additional walkers.
* Listing a subdirectory of an existing recursive cache will use the cache.
* All listing operations are fully streamable so the number of objects in a bucket no 
  longer dictates the amount of memory.
* Listings can be handled by any server within the cluster.
* Caches are cleaned up when out of date or superseded by a more recent one.

cmd/logger/logger.go

@@ -337,7 +337,7 @@ func logIf(ctx context.Context, err error, errKind ...interface{}) {
 	trace := getTrace(3)
 
 	// Get the cause for the Error
-	message := err.Error()
+	message := fmt.Sprintf("%v (%T)", err, err)
 	if req.DeploymentID == "" {
 		req.DeploymentID = globalDeploymentID
 	}