Add label filtering to source CRD

[JoaoBraveCoding]

What would you like to be added:

Add the possibility for an instance of external-dns to only process a subset of CRDs using label filter.

Why is this needed:

This is needed to allow us to deploy multiple instances of external-dns managing different RFC2136 zones each with up to two views.
Also for a high number of resources, it's more performance-oriented to query the API server for labels instead of annotations.

[fejta-bot]

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/lifecycle stale

[fejta-bot]

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Mark the issue as fresh with /remove-lifecycle rotten.
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/lifecycle rotten

[ytsarev]

/assign ytsarev

[fejta-bot]

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/close

[k8s-ci-robot]

@fejta-bot: Closing this issue.

In response to this:

Rotten issues close after 30d of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh with /remove-lifecycle rotten.

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/close

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[seanmalloy]

/reopen
/remove-lifecycle rotten

This new feature is implemented in PR #1461.

[k8s-ci-robot]

@seanmalloy: Reopened this issue.

In response to this:

/reopen
/remove-lifecycle rotten

This new feature is implemented in PR #1461.

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.