Terraform to accept job and exec IAM roles from variable similar to other modules (example ssc_model_deployment)

These [roles](https://github.com/SWOT-Confluence/h2ivdi/blob/main/terraform/modules/hivdi/main.tf#L16-L22) should have variables.tf option like in [ssc](https://github.com/SWOT-Confluence/ssc_model_deployment/blob/3.0.0/terraform/modules/ssc_model_deployment/variables.tf#L27-L35). 