Automatic merge from submit-queue

specify custom ca file to verify the keystone server

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**What this PR does / why we need it**:

Sometimes the keystone server's certificate is self-signed, mainly used for internal development, testing and etc.

For this kind of ca, we need a way to verify the keystone server.

Otherwise, below error will occur.

> x509: certificate signed by unknown authority

This patch provide a way to pass in a ca file to verify the keystone server when starting `kube-apiserver`.

**Which issue this PR fixes** : fixes #22695, #24984

**Special notes for your reviewer**:

**Release note**:

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