Ability to use IAM Roles on EKS for function triggers

[gkaskonas]

Is your feature request related to a problem? Please describe.
I want to use IAM roles by specifying the RoleARN in the trigger config (Or just allowing the operator to deal with it if it has permissions)
https://keda.sh/docs/1.4/scalers/aws-sqs/

Describe the solution you'd like
Either let us pass roleArn or let KEDA operator to deal with authentication

Describe alternatives you've considered
Using access keys is not a good practice

Additional context