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* Caches are cleaned up when out of date or superseded by a more recent one.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/data-update-tracker_test.go

@@ -169,7 +169,12 @@ func TestDataUpdateTracker(t *testing.T) {
 		})
 	}
 	// Cycle to history
-	_, err = dut.cycleFilter(ctx, 1, 2)
+	req := bloomFilterRequest{
+		Oldest:  1,
+		Current: 2,
+	}
+
+	_, err = dut.cycleFilter(ctx, req)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -200,7 +205,11 @@ func TestDataUpdateTracker(t *testing.T) {
 	if dut.current() != 2 {
 		t.Fatal("current idx after load not preserved. want 2, got:", dut.current())
 	}
-	bfr2, err := dut.cycleFilter(ctx, 1, 3)
+	req = bloomFilterRequest{
+		Oldest:  1,
+		Current: 3,
+	}
+	bfr2, err := dut.cycleFilter(ctx, req)
 	if err != nil {
 		t.Fatal(err)
 	}