(helm/v2-alpha): Fix namespace-scoped Role/RoleBinding filename collisions

Namespace-scoped Roles and RoleBindings with the same name in different
namespaces were overwriting each other's files. Now appends namespace to
filename (e.g., manager-role-infrastructure.yaml) to prevent collisions.

Adds comprehensive tests to validate RBAC resource placement and prevent
regressions.

Assisted-by: Cursor

Author: camilamacedo86