fix: Restore the nvidia distro (#2639)

# What does this PR do?

The `nvidia` distro was previously collapsed into the `starter` distro.
However, the `nvidia` distro was setup specifically to use NVIDIA NeMo
microservices as providers for all APIs and not just inference, which
means it was doing quite a bit more than what the `starter` distro
covers today.

We should work with our friends at NVIDIA to determine the best place to
maintain this distro long-term, but for now this restores the `nvidia`
distro and its docs back to where they were so that things continue to
work for their users.

## Test Plan

I ensure the `nvidia` distro could build, and run at least to the point
of complaining that I didn't provide the necessary API keys.

```
uv run llama stack build --template nvidia --image-type venv
uv run llama stack run llama_stack/templates/nvidia/run.yaml
```

I also made sure the docs website built and looks reasonable, with the
`nvidia` distro docs at the same URL it was previously (because it has
incoming links from official NVIDIA NeMo docs, among other places).

```
uv run --group docs sphinx-autobuild docs/source docs/build/html --write-all
```

Signed-off-by: Ben Browning <bbrownin@redhat.com>

llama_stack/templates/nvidia/nvidia.py

@@ -0,0 +1,150 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+from pathlib import Path
+
+from llama_stack.distribution.datatypes import ModelInput, Provider, ShieldInput, ToolGroupInput
+from llama_stack.providers.remote.datasetio.nvidia import NvidiaDatasetIOConfig
+from llama_stack.providers.remote.eval.nvidia import NVIDIAEvalConfig
+from llama_stack.providers.remote.inference.nvidia import NVIDIAConfig
+from llama_stack.providers.remote.inference.nvidia.models import MODEL_ENTRIES
+from llama_stack.providers.remote.safety.nvidia import NVIDIASafetyConfig
+from llama_stack.templates.template import DistributionTemplate, RunConfigSettings, get_model_registry
+
+
+def get_distribution_template() -> DistributionTemplate:
+    providers = {
+        "inference": ["remote::nvidia"],
+        "vector_io": ["inline::faiss"],
+        "safety": ["remote::nvidia"],
+        "agents": ["inline::meta-reference"],
+        "telemetry": ["inline::meta-reference"],
+        "eval": ["remote::nvidia"],
+        "post_training": ["remote::nvidia"],
+        "datasetio": ["inline::localfs", "remote::nvidia"],
+        "scoring": ["inline::basic"],
+        "tool_runtime": ["inline::rag-runtime"],
+    }
+
+    inference_provider = Provider(
+        provider_id="nvidia",
+        provider_type="remote::nvidia",
+        config=NVIDIAConfig.sample_run_config(),
+    )
+    safety_provider = Provider(
+        provider_id="nvidia",
+        provider_type="remote::nvidia",
+        config=NVIDIASafetyConfig.sample_run_config(),
+    )
+    datasetio_provider = Provider(
+        provider_id="nvidia",
+        provider_type="remote::nvidia",
+        config=NvidiaDatasetIOConfig.sample_run_config(),
+    )
+    eval_provider = Provider(
+        provider_id="nvidia",
+        provider_type="remote::nvidia",
+        config=NVIDIAEvalConfig.sample_run_config(),
+    )
+    inference_model = ModelInput(
+        model_id="${env.INFERENCE_MODEL}",
+        provider_id="nvidia",
+    )
+    safety_model = ModelInput(
+        model_id="${env.SAFETY_MODEL}",
+        provider_id="nvidia",
+    )
+
+    available_models = {
+        "nvidia": MODEL_ENTRIES,
+    }
+    default_tool_groups = [
+        ToolGroupInput(
+            toolgroup_id="builtin::rag",
+            provider_id="rag-runtime",
+        ),
+    ]
+
+    default_models = get_model_registry(available_models)
+    return DistributionTemplate(
+        name="nvidia",
+        distro_type="self_hosted",
+        description="Use NVIDIA NIM for running LLM inference, evaluation and safety",
+        container_image=None,
+        template_path=Path(__file__).parent / "doc_template.md",
+        providers=providers,
+        available_models_by_provider=available_models,
+        run_configs={
+            "run.yaml": RunConfigSettings(
+                provider_overrides={
+                    "inference": [inference_provider],
+                    "datasetio": [datasetio_provider],
+                    "eval": [eval_provider],
+                },
+                default_models=default_models,
+                default_tool_groups=default_tool_groups,
+            ),
+            "run-with-safety.yaml": RunConfigSettings(
+                provider_overrides={
+                    "inference": [
+                        inference_provider,
+                        safety_provider,
+                    ],
+                    "eval": [eval_provider],
+                },
+                default_models=[inference_model, safety_model],
+                default_shields=[ShieldInput(shield_id="${env.SAFETY_MODEL}", provider_id="nvidia")],
+                default_tool_groups=default_tool_groups,
+            ),
+        },
+        run_config_env_vars={
+            "NVIDIA_API_KEY": (
+                "",
+                "NVIDIA API Key",
+            ),
+            "NVIDIA_APPEND_API_VERSION": (
+                "True",
+                "Whether to append the API version to the base_url",
+            ),
+            ## Nemo Customizer related variables
+            "NVIDIA_DATASET_NAMESPACE": (
+                "default",
+                "NVIDIA Dataset Namespace",
+            ),
+            "NVIDIA_PROJECT_ID": (
+                "test-project",
+                "NVIDIA Project ID",
+            ),
+            "NVIDIA_CUSTOMIZER_URL": (
+                "https://customizer.api.nvidia.com",
+                "NVIDIA Customizer URL",
+            ),
+            "NVIDIA_OUTPUT_MODEL_DIR": (
+                "test-example-model@v1",
+                "NVIDIA Output Model Directory",
+            ),
+            "GUARDRAILS_SERVICE_URL": (
+                "http://0.0.0.0:7331",
+                "URL for the NeMo Guardrails Service",
+            ),
+            "NVIDIA_GUARDRAILS_CONFIG_ID": (
+                "self-check",
+                "NVIDIA Guardrail Configuration ID",
+            ),
+            "NVIDIA_EVALUATOR_URL": (
+                "http://0.0.0.0:7331",
+                "URL for the NeMo Evaluator Service",
+            ),
+            "INFERENCE_MODEL": (
+                "Llama3.1-8B-Instruct",
+                "Inference model",
+            ),
+            "SAFETY_MODEL": (
+                "meta/llama-3.1-8b-instruct",
+                "Name of the model to use for safety",
+            ),
+        },
+    )