Fix links after kubernetes renamed access-kubernetes to extend-kuberntes-api

[fabianvf]

Description of the change:
Fixes broken links caused by kubernetes rename of a group of docs

Motivation for the change:
Our CI is failing

[estroz]

/cherry-pick v0.18.x

[openshift-cherrypick-robot]

@estroz: new pull request could not be created: status code 422 not one of [201], body: {"message":"Validation Failed","errors":[{"resource":"PullRequest","field":"head","code":"invalid"}],"documentation_url":"https://developer.github.com/v3/pulls/#create-a-pull-request"}

In response to this:

/cherry-pick v0.18.x

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[estroz]

/cherry-pick v0.17.x

[openshift-cherrypick-robot]

@estroz: #3219 failed to apply on top of branch "v0.17.x":

.git/rebase-apply/patch:19: trailing whitespace.
Currently, SDK tool does not support and will not generate automatically the CRD's using the [OpenAPI](https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#validation) spec to perform validations. 
warning: 1 line adds whitespace errors.
error: Failed to merge in the changes.
Using index info to reconstruct a base tree...
M	website/content/en/docs/ansible/reference/finalizers.md
A	website/content/en/docs/golang/migrating-existing-apis.md
M	website/content/en/docs/golang/quickstart.md
M	website/content/en/docs/golang/references/client.md
A	website/content/en/docs/operator-capabilities.md
Falling back to patching base and 3-way merge...
Auto-merging website/content/en/docs/golang/references/client.md
Auto-merging website/content/en/docs/golang/quickstart.md
Auto-merging website/content/en/docs/ansible/reference/finalizers.md
CONFLICT (content): Merge conflict in website/content/en/docs/ansible/reference/finalizers.md
Auto-merging doc/user/migrating-existing-apis.md
Auto-merging doc/operator-capabilities.md
Patch failed at 0001 Fix links after kubernetes renamed access-kubernetes to extend-kubernetes-api

In response to this:

/cherry-pick v0.17.x

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.