Add procedure about how to delete a TiKV Pod and make it join the cluster as a new store

[DanielZhangQD]

Change Request

This repository is ONLY used to solve issues related to TiDB Operator documentation. For other issues (related to TiDB, PD, etc), please move to other repositories.

Please answer the following questions before submitting your issue. Thanks!

1. Describe what you find is inappropriate or missing in the existing docs.

• 1. Delete store with pd-ctl
• 2. Refer to https://docs.pingcap.com/tidb-in-kubernetes/dev/maintain-a-kubernetes-node#maintain-an-irrecoverable-node-in-a-short-term steps 4-6, after that, tikv Pod will join the cluster as a new store

2. Describe your suggestion or addition.

3. Provide some reference materials (documents, websites, etc) if you could.

[DanielZhangQD]

Please also cover the following case:

3. If indeed need to replace the nodes and EBS 3.1 Scale out new nodes that in the same AZ with the ones to be replaced 3.2 Cordon the old nodes 3.3 Delete the stores with pd-ctl, wait for the stores to become tombstone 3.4 Delete the PVC 3.5 Delete the Pod, check that the Pods are scheduled to the new Nodes 3.6 Delete the old nodes