Add support to stop TiDB gracefully (#2810)

[ti-srebot]

cherry-pick #2810 to release-1.1

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What problem does this PR solve?

This pr add terminationGracePeriodSeconds and lifecycle to TidbCluster spec.tidb attribute.

User can use these two attributes to stop TiDB server gracefully:

1. set spec.tidb.terminationGracePeriodSeconds to a proper value, for exmaple: 600 (10 minutes).
2. set spec.tidb.lifecycle to: kill -QUIT 1;

# IT IS NOT SUITABLE FOR PRODUCTION USE.
# This YAML describes a basic TiDB cluster with minimum resource requirements,
# which should be able to run in any Kubernetes cluster with storage support.
apiVersion: pingcap.com/v1alpha1
kind: TidbCluster
metadata:
  name: basic
spec:
  version: v4.0.0
  timezone: UTC
  pvReclaimPolicy: Delete
  discovery: {}
  pd:
    baseImage: pingcap/pd
    replicas: 1
    # if storageClassName is not set, the default Storage Class of the Kubernetes cluster will be used
    # storageClassName: local-storage
    requests:
      storage: "1Gi"
    config: {}
  tikv:
    baseImage: pingcap/tikv
    replicas: 1
    # if storageClassName is not set, the default Storage Class of the Kubernetes cluster will be used
    # storageClassName: local-storage
    requests:
      storage: "1Gi"
    config: {}
  tidb:
    baseImage: pingcap/tidb
    replicas: 1
    service:
      type: ClusterIP
    config: {}
    terminationGracePeriodSeconds: 600
    lifecycle:
      preStop:
        exec:
          command: ["kill", "-QUIT", "1"]

The TiDB server will go graceful shutting down to wait for all clients to close the connection until k8s force kill the TiDB container(10 minutes later).

fixes: #2597

What is changed and how does it work?

Check List

Tests

• Unit test
• E2E test
• Stability test
• Manual test (add detailed scripts or steps below)
• No code

Code changes

• Has Go code change
• Has CI related scripts change
• Has Terraform scripts change

Side effects

• Breaking backward compatibility

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Does this PR introduce a user-facing change?:

Support configuring container lifecycle hooks and `terminationGracePeriodSeconds` in TiDB spec

[cofyc]

@weekface can you cherry-pick this PR manually? we have conflicts in auto-generated files, I guess we need to regenerate them on release-1.1.

[DanielZhangQD]

Close via #2849