Role ARN Prefix

**What would you like to be added**:

Add a CLI switch to allow for adding an IAM Role prefix. This feature should be overridden if a full ARN is detected in a ServiceAccount annotation.

**Why is this needed**:

This allows for shorthand in service account annotations, further allowing, deployments to remain similar across accounts.

The issue names no files or tests. Start by locating the CLI option parsing and ServiceAccount annotation handling, then verify that a shorthand role uses the configured prefix while a full ARN takes precedence; done means both annotation forms produce the intended role ARN.

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