add support for EventRateLimit plugin configuration

[alegrey91]

What type of PR is this?

/kind feature

What this PR does / why we need it:
Currently is not possible to configure the EventRateLimit admission plugin (and the others too) through kubespray. This could be really useful in the hardening perspective (example CIS 1.2.9 of CIS Kubernetes Benchmark).

Which issue(s) this PR fixes:

Fixes #8686

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

The user can decide to enable admission plugin configuartion through kube_apiserver_admission_control_config_file: true and configure the EventRateLimit using the following structure:

kube_apiserver_admission_event_rate_limits:
<limit_name>:
  type: <limit_type>
  qps: <qps_value>
  burst: <burst_value>
  cache_size: <cache_size_value>

Does this PR introduce a user-facing change?:

add support for `EventRateLimit` plugin configuration

[k8s-ci-robot]

Hi @alegrey91. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[oomichi]

Thank you for doing this!
Just a few comments.

/ok-to-test

[cristicalin]

@alegrey91 note that you might need to rebase this PR on the latest state of master branch for all the CI jobs to succeed.

[alegrey91]

@alegrey91 note that you might need to rebase this PR on the latest state of master branch for all the CI jobs to succeed.

Ok @cristicalin, I'll do it asap :)

[alegrey91]

Done!

[cristicalin]

Thanks for doing this @alegrey91 !

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alegrey91, cristicalin

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[oomichi]

Thanks for updating @alegrey91

/lgtm