etcd/backup: native ansible modules instead of shell

[VannTen]

What type of PR is this?
/kind cleanup

What this PR does / why we need it:

This make native ansible features (dry-run, changed state) easier to
have, and should have a minimal performance impact, since it only runs
on the etcd members.

Does this PR introduce a user-facing change?:

etcd/backup: use native ansible modules instead of shell

[k8s-ci-robot]

Hi @VannTen. 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[yankay]

/ok-to-test

[floryut]

@VannTen Thank you for the PR

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: floryut, VannTen

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[MrFreezeex]

Thanks!
/lgtm