[zh] Part1:updated the term "群集" to "集群"

[mengjiao-liu]

see #33643 (comment)

在中文本地化中其他页面存在将“cluster” 翻译为“群集”的情况，
术语对照表的建议是翻译为 “集群”，因此，此 PR 修改此术语翻译。

因为涉及到的文件比较多，这个 PR 只修改 “cluster”术语，不修改涉及到的文件的格式或者其他错误（比如，中英文空格等问题）。

此 PR 修改的文件：

content/zh/blog/_posts/2015-03-00-Welcome-To-Kubernetes-Blog.md
content/zh/blog/_posts/2016-07-00-Dashboard-Web-Interface-For-Kubernetes.md
content/zh/blog/_posts/2016-07-00-stateful-applications-in-containers-kubernetes.md
content/zh/blog/_posts/2018-06-28-Airflow-Kubernetes-Operator.md
content/zh/blog/_posts/2018-07-10-coredns-ga.md
content/zh/blog/_posts/2018-07-11-dynamic-kubelet-configuration.md
content/zh/blog/_posts/2018-10-10-runtimeclass.md
content/zh/blog/_posts/2019-03-28-PID-Limiting.md
content/zh/blog/_posts/2019-08-06-OPA-Gatekeeper-Policy-and-Governance-for-Kubernetes.md
content/zh/docs/concepts/cluster-administration/networking.md
content/zh/docs/concepts/cluster-administration/proxies.md
content/zh/docs/concepts/storage/dynamic-provisioning.md
content/zh/docs/concepts/storage/storage-classes.md
content/zh/docs/reference/glossary/cluster-operations.md
content/zh/docs/reference/kubectl/docker-cli-to-kubectl.md
content/zh/docs/reference/setup-tools/kubeadm/generated/kubeadm_upgrade_node_phase_kubelet-config.md
content/zh/docs/setup/production-environment/tools/kops.md
content/zh/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm.md
content/zh/docs/setup/production-environment/tools/kubeadm/high-availability.md
content/zh/docs/setup/production-environment/tools/kubeadm/setup-ha-etcd-with-kubeadm.md
content/zh/docs/tasks/access-application-cluster/configure-access-multiple-clusters.md
content/zh/docs/tasks/administer-cluster/cluster-upgrade.md
content/zh/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods.md
content/zh/docs/tasks/administer-cluster/manage-resources/memory-constraint-namespace.md
content/zh/docs/tasks/administer-cluster/namespaces-walkthrough.md
content/zh/docs/tasks/administer-cluster/namespaces.md
content/zh/docs/tasks/administer-cluster/running-cloud-controller.md
content/zh/docs/tasks/administer-cluster/securing-a-cluster.md
content/zh/docs/tasks/extend-kubernetes/configure-aggregation-layer.md
content/zh/docs/tutorials/kubernetes-basics/deploy-app/deploy-intro.html
content/zh/docs/tutorials/kubernetes-basics/explore/explore-intro.html
content/zh/docs/tutorials/security/apparmor.md
content/zh/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume.md

/cc @tengqm @howieyuen

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[tengqm]

Thanks for this big effort. I'm wondering if all the files touched by this PR have already been sync'ed properly?

[howieyuen]

./scripts/lsync.sh checks if the English version of a page has changed since a localized page has been committed.
so commit date is extremely important.

[mengjiao-liu]

我重新检查了文件是否同步，此PR 仅更新了已经同步的文件，并创建了 issue #33735 用于追踪剩下的未同步的文件。

涉及的文件较多，请尽快审核，避免频繁 rebase。 @tengqm @howieyuen

[howieyuen]

我重新检查了文件是否同步，此PR 仅更新了已经同步的文件，并创建了 issue #33735 用于追踪剩下的未同步的文件。

涉及的文件较多，请尽快审核，避免频繁 rebase。 @tengqm @howieyuen

nice work

[mengjiao-liu]

Please review as soon as possible. @howieyuen

[howieyuen]

/approve
/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: howieyuen

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[k8s-ci-robot]

LGTM label has been added.

Git tree hash: c5b90cfe93a3182a663c7d3b4dfd545d5a1cd696

[tengqm]

/hold cancel

Thanks.