cri: support blockio class in pod and container annotations

This patch adds support for a container annotation and two separate
pod annotations for controlling the blockio class of containers.

The container annotation can be used by a CRI client:
  "io.kubernetes.cri.blockio-class"

Pod annotations specify the blockio class in the K8s pod spec level:
  "blockio.resources.beta.kubernetes.io/pod"
  (pod-wide default for all containers within)

  "blockio.resources.beta.kubernetes.io/container.<container_name>"
  (container-specific overrides)

Correspondingly, this patch adds support for --blockio-class and
--blockio-config-file to ctr, too.

This implementation follows the resource class annotation pattern
introduced in RDT and merged in commit 893701220.

Signed-off-by: Antti Kervinen <antti.kervinen@intel.com>

vendor/github.com/intel/goresctrl/pkg/cgroups/fsios.go

@@ -0,0 +1,63 @@
+// Copyright 2021 Intel Corporation. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// This module provides the native implementation of the filesystem
+// interface (fsi).
+
+package cgroups
+
+import (
+	"os"
+	"path/filepath"
+)
+
+type fsOs struct{}
+
+type osFile struct {
+	file *os.File
+}
+
+func newFsiOS() fsiIface {
+	return fsOs{}
+}
+
+func (fsOs) OpenFile(name string, flag int, perm os.FileMode) (fileIface, error) {
+	f, err := os.OpenFile(name, flag, perm)
+	return osFile{f}, err
+}
+
+func (fsOs) Open(name string) (fileIface, error) {
+	f, err := os.Open(name)
+	return osFile{f}, err
+}
+
+func (fsOs) Lstat(name string) (os.FileInfo, error) {
+	return os.Lstat(name)
+}
+
+func (fsOs) Walk(root string, walkFn filepath.WalkFunc) error {
+	return filepath.Walk(root, walkFn)
+}
+
+func (osf osFile) Write(b []byte) (n int, err error) {
+	return osf.file.Write(b)
+}
+
+func (osf osFile) Read(b []byte) (n int, err error) {
+	return osf.file.Read(b)
+}
+
+func (osf osFile) Close() error {
+	return osf.file.Close()
+}