[release-2.27] Add manual option to the external_cloud_provider variable

[k8s-infra-cherrypick-robot]

This is an automated cherry-pick of #11883

/assign tico88612

The `external_cloud_provider` support `manual` option lets users install the cloud controller manager themselves.

[tico88612]

/ok-to-test
/lgtm

[VannTen]

Hum, is there a particular reason to backport this ? I mean, we would usually only backport bug-fixes (or their dependencies)

[tico88612]

I'd like to say if this #11878 report needs to be added in v2.27.1, and if it doesn't match our original policy, it's fine if it can be closed.

[tico88612]

/remove-lgtm

[VannTen]

Oh, do you mean that was technically fixing a regression ? In that, case, yeah ofc we should backport this 👍

[tico88612]

I didn't design this feature in the first place, maybe the people before me didn't consider this part either. 😂
However, this minor fix will fill a new need for some users. Let's do this!

/lgtm

[VannTen]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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