Implements InstancesV2 interface

[mmerkes]

What type of PR is this?

/kind cleanup /kind feature

What this PR does / why we need it:

The InstancesV2 interface is the path forward for cloud providers. To enable new changes, like providing custom labels, we need to migrate to InstancesV2 as they won't be implemented in the original Instances interface.

This change is needed to prepare to support #300

Which issue(s) this PR fixes: N/A

Special notes for your reviewer:

I've added unit tests here and the automation should run. I'll do some manual testing with an EKS cluster, but if you have suggestions on things I should test specifically, let me know.

Does this PR introduce a user-facing change?:

Migrate to InstancesV2 interface

[k8s-ci-robot]

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[mmerkes]

/assign @cartermckinnon @dims

[mmerkes]

/retest

[dims]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dims, olemarkus

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/kubernetes/cloud-provider-aws/blob/master/OWNERS)~~ [dims,olemarkus] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[olemarkus]

/lgtm