Add initial support for bucket lifecycle (#7563)

This PR is based off @sinhaashish's PR for object lifecycle
management, which includes support only for,
- Expiration of object
- Filter using object prefix (_not_ object tags)

N B the code for actual expiration of objects will be included in a
subsequent PR.

cmd/test-utils_test.go

@@ -365,6 +365,9 @@ func UnstartedTestServer(t TestErrHandler, instanceType string) TestServer {
 	globalNotificationSys = NewNotificationSys(globalServerConfig, testServer.Disks)
 	globalNotificationSys.Init(objLayer)
 
+	globalLifecycleSys = NewLifecycleSys()
+	globalLifecycleSys.Init(objLayer)
+
 	return testServer
 }