feat: allows users to have more control on DNS

[eminaktas]

Kubespray should give us more control over DNS. The current behavior limits users to configure DNS settings. The attempts or timeout options are hard coded. No way to fully configure searchdomains.

This PR introduces:

• Users can define attempts and timeout options.
  • The hard-coded values for both options were 2. It is set as default values.
• There was no way to remove default searchdomains.
  • remove_default_searchdomains will remove default searchdomains.
• searchdomains can be fully configured
• Both nodelocaldns and coredns IPs won't be added to nameserverentries together. It will be added depending on the condition.

What type of PR is this?

/kind feature

Does this PR introduce a user-facing change?:

No, it adds more functionalty to DNS settings.

Add more functionalty to DNS configuration

Signed-off-by: eminaktas eminaktas34@gmail.com

[k8s-ci-robot]

Hi @eminaktas. Thanks for your PR.

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[oomichi]

Nice work!

/ok-to-test
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: eminaktas, oomichi

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[cristicalin]

Thanks @eminaktas

/lgtm