Integrate with TiDB v3.1 for configuration parameters update

[DanielZhangQD]

Feature Request

Is your feature request related to a problem? Please describe:

There are configuration parameters update, e.g. add, remove, type change, default value modification, etc. for the components of TiDB v3.1.

Describe the feature you'd like:

TiDB Operator needs to update for the configuration changes to support TiDB v3.1.
Describe alternatives you've considered:

Teachability, Documentation, Adoption, Migration Strategy:

[Yisaer]

According to the document about the configuration in the reference for tidb-server / tikv-server / pd-server, there is a few newly added configuration for these components. And the operator already has updated it. So I think there is no need for this issue or you can provide more detail?

@DanielZhangQD

[DanielZhangQD]

@Yisaer If you are sure that all the newly added parameters in TiDB v3.1 are supported, feel free to close this issue.

[Yisaer]

For tidb: #1906
For pd: #1928
For tikv: there is no change.