Add option to deploy aws ipam controller

[DockToFuture]

How to categorize this PR?

/area networking
/kind enhancement
/platform aws

What this PR does / why we need it:
The aws-ipam-controller is required to support prefix delegation for IPv6 and dual-stack mode. With this pull request the aws-ipam-controller can be enabled in the gardener-extension-provider-aws-configmap as feature gate. Once it is enabled it disables theallocate-node-cidrs field in the cloud-controller-manager and the kube-controller-manager for IPv6 or dual-stack shoot clusters.

apiVersion: v1
kind: ConfigMap
data:
  config.yaml: |
    ---
    apiVersion: aws.provider.extensions.config.gardener.cloud/v1alpha1
    kind: ControllerConfiguration
    ...
    featureGates:
      EnableIPAMController: true

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Release note:

The aws-ipam-controller can now be enabled  in the `gardener-extension-provider-aws-configmap` as feature gate. It replaces the IPAM of the cloud-controller-manager and kube-controller-manager and supports additionally prefix delegation in case of IPv6 or dual-stack. 

[kon-angelo]

/assign

[kon-angelo]

@DockToFuture do you think that this should be exposed on a shoot level ? Would it make sense as a seed featuregate instead ? I don't see value in the user manually fiddling with the IPAM - rather it is something that we know from the IP family support and we can configure it ourselves.

[gardener-robot]

@DockToFuture You need rebase this pull request with latest master branch. Please check.

[hebelsan]

/lgtm

[DockToFuture]

Can we get this change in?

[kon-angelo]

/test

[testmachinery]

Testrun: e2e-g5qxr
Workflow: e2e-g5qxr-wf
Phase: Succeeded

+---------------------+-----------------------------+-----------+----------+
|        NAME         |            STEP             |   PHASE   | DURATION |
+---------------------+-----------------------------+-----------+----------+
| infrastructure-test | infrastructure-test-tf      | Succeeded | 35m30s   |
| infrastructure-test | infrastructure-test-flow    | Succeeded | 26m7s    |
| infrastructure-test | infrastructure-test-migrate | Succeeded | 30m47s   |
| infrastructure-test | infrastructure-test-recover | Succeeded | 27m38s   |
| bastion-test        | bastion-test                | Succeeded | 8m29s    |
| dnsrecord-test      | dnsrecord-test              | Succeeded | 6m10s    |
+---------------------+-----------------------------+-----------+----------+

stale