feat: add support for IRSA and kiam/kube2iam

[scottd018]

Fixes #190

This PR does the following:

• Adds support for the AWS provider to use either IRSA, kiam, or kube2iam
• Adds spec fields spec.provider.aws.assumeRole.id (AWS Role ARN) and spec.provider.aws.assumeRole.strategy (type of irsa, kiam, or kube2iam)
• Updates the webhook to validate either credentials -OR- spec.provider.aws.assumeRole is set to allow external-dns controller to update DNS
• Adds the appropriate eks.amazonaws.com/role-arn service account annotation if IRSA is requested
• Adds the appropriate iam.amazonaws.com/role if kiam/kube2iam is requested
• Adds tests for use cases

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: scottd018 Once this PR has been reviewed and has the lgtm label, please assign candita for approval. For more information see the Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files: - **[OWNERS](https://github.com/openshift/external-dns-operator/blob/main/OWNERS)** Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[openshift-ci[bot]]

@scottd018: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/verify	07f6aba75890d64394209f051722b0e8320d3382	link	true	/test verify

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).

[openshift-bot]

Issues go stale after 90d of inactivity.

Mark the issue as fresh by commenting /remove-lifecycle stale. Stale issues rot after an additional 30d of inactivity and eventually close. Exclude this issue from closing by commenting /lifecycle frozen.

If this issue is safe to close now please do so with /close.

/lifecycle stale

[openshift-bot]

Stale issues rot after 30d of inactivity.

Mark the issue as fresh by commenting /remove-lifecycle rotten. Rotten issues close after an additional 30d of inactivity. Exclude this issue from closing by commenting /lifecycle frozen.

If this issue is safe to close now please do so with /close.

/lifecycle rotten /remove-lifecycle stale

[openshift-bot]

Rotten issues close after 30d of inactivity.

Reopen the issue by commenting /reopen. Mark the issue as fresh by commenting /remove-lifecycle rotten. Exclude this issue from closing again by commenting /lifecycle frozen.

/close

[openshift-ci[bot]]

@openshift-bot: Closed this PR.

In response to [this](https://github.com/openshift/external-dns-operator/pull/191#issuecomment-1646345769): >Rotten issues close after 30d of inactivity. > >Reopen the issue by commenting `/reopen`. >Mark the issue as fresh by commenting `/remove-lifecycle rotten`. >Exclude this issue from closing again by commenting `/lifecycle frozen`. > >/close Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.