v1beta3 API Changes

[richardcase]

/kind refactor
/kind api-change
/priority important-soon
/triage accepted

Describe the solution you'd like

An issue to track the API changes that are required in the next API version bump.

Changes:

• Removal of deprecated fields from AWSManagedMachinePool (as a result of the launch template work)
• Make optional API fields consistently pointers (or not pointers) #3243

Anything else you would like to add:

This captures some changes that didn't make it into v1beta2 (v2.0.0) from #2355

### Tasks
- [ ] https://github.com/kubernetes-sigs/cluster-api-provider-aws/issues/1166
- [ ] The IamInstanceProfile property on AWSLaunchTemplates should be changed to IAMInstanceProfile (capital IAM) to be consistent with the same property on AWSMachineSpec and Go style guidelines on acronyms.  See: https://github.com/kubernetes-sigs/cluster-api-provider-aws/blob/3586b3b25153ad525119199dfc9544b69ad0d15f/exp/api/v1beta2/types.go
- [ ] https://github.com/kubernetes-sigs/cluster-api-provider-aws/issues/4333
- [ ] Removal of deprecated fields from AWSManagedMachinePool (as a result of the launch template work)
- [ ] https://github.com/kubernetes-sigs/cluster-api-provider-aws/issues/3243
- [ ] Change the version field on AWSManagedControlPlane, option 1) from @damdo suggestions in #5209

[Ankitasw]

Also #3243

[richardcase]

Also #3243

Added to the list

[AverageMarcus]

The IamInstanceProfile property on AWSLaunchTemplates should be changed to IAMInstanceProfile (capital IAM) to be consistent with the same property on AWSMachineSpec and Go style guidelines on acronyms.

See: https://github.com/kubernetes-sigs/cluster-api-provider-aws/blob/3586b3b25153ad525119199dfc9544b69ad0d15f/exp/api/v1beta2/types.go

[Ankitasw]

Also #1166

[k8s-triage-robot]

This issue is labeled with priority/important-soon but has not been updated in over 90 days, and should be re-triaged.
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/remove-triage accepted

[k8s-triage-robot]

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/lifecycle stale

[richardcase]

/remove-lifecycle stale