Support ALB Name Customization for ROKS Clusters via Terraform

Currently, when a ROKS cluster is created through Terraform, the associated ALB is created with a default name.

Although the ALB name can be changed later through the IBM Cloud console, there is currently no way to define a custom ALB name during cluster provisioning using Terraform.

It would be very useful to have the ability to specify the ALB name through Terraform, allowing users to manage this configuration through Infrastructure as Code and avoid manual post-deployment changes.

This would improve automation, consistency, and governance across environments.

This feature would help organizations that manage their infrastructure through Terraform and GitOps practices, ensuring consistent naming standards across environments without requiring manual intervention through the IBM Cloud console.