openapi: add clusters api (#2194)

[ti-chi-bot]

This is an automated cherry-pick of #2194

What problem does this PR solve?

1982

• add cluster api (list/offline master and worker node)

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• No code

Code changes

• Has exported function/method change
• Has exported variable/fields change

Side effects

Related changes

• Need to cherry-pick to the release branch

[ti-chi-bot]

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[Ehco1996]

no need to cherry pick