Move `profiles_enabled` logic out of `providers.tf` and into `iam-roles`
What
- For Terraform roles and profiles used in
providers.tf
, returnnull
for unused option - Rename variables to
overridable_*
and update documentation to recommendvariables_override.tf
for customization
Why
- Prepare for
providers.tf
updates to support dynamic Terraform roles - ARB decision on customization compatible with vendoring