Support bucket versioning (#9377)

- Implement a new xl.json 2.0.0 format to support,
  this moves the entire marshaling logic to POSIX
  layer, top layer always consumes a common FileInfo
  construct which simplifies the metadata reads.
- Implement list object versions
- Migrate to siphash from crchash for new deployments
  for object placements.

Fixes #2111

cmd/handler-utils.go

@@ -445,7 +445,7 @@ func errorResponseHandler(w http.ResponseWriter, r *http.Request) {
 
 // gets host name for current node
 func getHostName(r *http.Request) (hostName string) {
-	if globalIsDistXL {
+	if globalIsDistErasure {
 		hostName = GetLocalPeer(globalEndpoints)
 	} else {
 		hostName = r.Host