RFC: AWS KMS credentials config restructure & EKS workload authentication

[Robert Young]

We have a new design proposal to consider which covers:

1. refactoring to introduce a `credentials` node to the AWS KMS configuration
2. Adds two new credential providers for Amazon EKS pods.
 i. IRSA exchanges a projected OIDC token via STS AssumeRoleWithWebIdentity
 ii. Pod Identity calls the local Pod Identity Agent.

https://github.com/kroxylicious/design/pull/97

Thanks to contributor Oleksiy Pylypenko

[Robert Young]

Hi! We now have two approvals on this design, Keith & me.

I intend to merge this tomorrow, around 10pm UTC on Monday if there are no objections by then.

Thanks
Rob Young

[Robert Young]

I just merged this proposal.

Thanks again Oleksiy!