Describe the feature:
Support the use of AWS EKS IAM roles for service accounts.

This requires two things to take place:

1. Filebeat (and potentially other charts) do not appear to be use an AWS SDK version that supports assuming an IAM role via an OIDC web identity token file (sts:AssumeRoleWithWebIdentity). This is required in order to use EKS's IAM roles for service accounts feature. AWS SDK version requirements are here.

2. Charts also need to support service account annotations described in issue Please allow annotations for the ServiceAccount resources in your charts #627

Describe a specific use case for the feature:
Provide AWS IAM roles to pods instead of supplying credentials directly in configuration. Adding the following annotation to the service account would allow the use of the corresponding role.

annotations:
  eks.amazonaws.com/role-arn: arn:aws:iam::<ACCOUNT-ID>:role/<ROLE-NAME>