ray.sub requires submission from NeMo RL home directory, blocking external workflow organization

**Describe the bug**

The ray.sub script currently requires users to submit SLURM jobs from the NeMo RL repository directory, which prevents users from organizing their training scripts and experiments in separate project directories. This creates workflow friction and forces tight coupling between framework code and user code.

**Impact**

Users cannot maintain their experiment code separate from the framework installation without workarounds. This creates friction for:
- Teams using separate version control for experiments
- Users running multiple projects with one NeMo RL installation