Translate concepts/extend-kubernetes/api-extension/apiserver-aggregation/ into Japanese

[hasebe]

This is a...

• Feature Request
• Bug Report

Problem:
No concepts/extend-kubernetes/api-extension/apiserver-aggregation.md in Japanese.

Proposed Solution:
Copy a file from en contents to content/ja/docs/concepts/extend-kubernetes/api-extension/apiserver-aggregation.md and translate it into Japanese.

Page to Update:
https://kubernetes.io/ja/docs/extend-kubernetes/api-extension/apiserver-aggregation/

[hasebe]

/language ja

[hasebe]

/assign @hasebe

[sftim]

/priority backlog
/lifecycle active

[oke-py]

/close

[k8s-ci-robot]

@oke-py: Closing this issue.

In response to this:

/close

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