fix: Restore the nvidia distro

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.

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

llama_stack/templates/nvidia/build.yaml

@@ -0,0 +1,29 @@
+version: 2
+distribution_spec:
+  description: Use NVIDIA NIM for running LLM inference, evaluation and safety
+  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
+image_type: conda
+additional_pip_packages:
+- aiosqlite
+- sqlalchemy[asyncio]