fix(cloudflare): reduce dns & custom hostnames list api calls

[vflaux]

Description

List cloudflare DNS records & custom hostnames only once per zone instead of one per change.

For this to work we need to reflect changes made on the api into CustomHostnamesMap & DNSRecordsMap. (Only updating CustomHostnamesMap is actually needed for the tests to pass, so maybe we could ignore changes with DNSRecordsMap)

I don't use custom hostnames so I have not tested it in a cluster.

Checklist

• Unit tests updated
• End user documentation updated

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @vflaux. 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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[k8s-ci-robot]

PR needs rebase.

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