Auto-generate distro yamls + docs (#468)

# What does this PR do?

Automatically generates
- build.yaml
- run.yaml
- run-with-safety.yaml
- parts of markdown docs

for the distributions.

## Test Plan

At this point, this only updates the YAMLs and the docs. Some testing
(especially with ollama and vllm) has been performed but needs to be
much more tested.

llama_stack/templates/remote-vllm/doc_template.md

@@ -0,0 +1,119 @@
+# Remote vLLM Distribution
+
+The `llamastack/distribution-{{ name }}` distribution consists of the following provider configurations:
+
+{{ providers_table }}
+
+You can use this distribution if you have GPUs and want to run an independent vLLM server container for running inference.
+
+{% if run_config_env_vars %}
+### Environment Variables
+
+The following environment variables can be configured:
+
+{% for var, (default_value, description) in run_config_env_vars.items() %}
+- `{{ var }}`: {{ description }} (default: `{{ default_value }}`)
+{% endfor %}
+{% endif %}
+
+
+## Setting up vLLM server
+
+Please check the [vLLM Documentation](https://docs.vllm.ai/en/v0.5.5/serving/deploying_with_docker.html) to get a vLLM endpoint. Here is a sample script to start a vLLM server locally via Docker:
+
+```bash
+export INFERENCE_PORT=8000
+export INFERENCE_MODEL=meta-llama/Llama-3.2-3B-Instruct
+export CUDA_VISIBLE_DEVICES=0
+
+docker run \
+    --runtime nvidia \
+    --gpus $CUDA_VISIBLE_DEVICES \
+    -v ~/.cache/huggingface:/root/.cache/huggingface \
+    --env "HUGGING_FACE_HUB_TOKEN=$HF_TOKEN" \
+    -p $INFERENCE_PORT:$INFERENCE_PORT \
+    --ipc=host \
+    vllm/vllm-openai:latest \
+    --model $INFERENCE_MODEL \
+    --port $INFERENCE_PORT
+```
+
+If you are using Llama Stack Safety / Shield APIs, then you will need to also run another instance of a vLLM with a corresponding safety model like `meta-llama/Llama-Guard-3-1B` using a script like:
+
+```bash
+export SAFETY_PORT=8081
+export SAFETY_MODEL=meta-llama/Llama-Guard-3-1B
+export CUDA_VISIBLE_DEVICES=1
+
+docker run \
+    --runtime nvidia \
+    --gpus $CUDA_VISIBLE_DEVICES \
+    -v ~/.cache/huggingface:/root/.cache/huggingface \
+    --env "HUGGING_FACE_HUB_TOKEN=$HF_TOKEN" \
+    -p $SAFETY_PORT:$SAFETY_PORT \
+    --ipc=host \
+    vllm/vllm-openai:latest \
+    --model $SAFETY_MODEL \
+    --port $SAFETY_PORT
+```
+
+## Running Llama Stack
+
+Now you are ready to run Llama Stack with vLLM as the inference provider. You can do this via Conda (build code) or Docker which has a pre-built image.
+
+### Via Docker
+
+This method allows you to get started quickly without having to build the distribution code.
+
+```bash
+LLAMA_STACK_PORT=5001
+docker run \
+  -it \
+  -p $LLAMA_STACK_PORT:$LLAMA_STACK_PORT \
+  -v ./run.yaml:/root/my-run.yaml \
+  llamastack/distribution-{{ name }} \
+  /root/my-run.yaml \
+  --port $LLAMA_STACK_PORT \
+  --env INFERENCE_MODEL=$INFERENCE_MODEL \
+  --env VLLM_URL=http://host.docker.internal:$INFERENCE_PORT \
+```
+
+If you are using Llama Stack Safety / Shield APIs, use:
+
+```bash
+docker run \
+  -it \
+  -p $LLAMA_STACK_PORT:$LLAMA_STACK_PORT \
+  -v ./run-with-safety.yaml:/root/my-run.yaml \
+  llamastack/distribution-{{ name }} \
+  /root/my-run.yaml \
+  --port $LLAMA_STACK_PORT \
+  --env INFERENCE_MODEL=$INFERENCE_MODEL \
+  --env VLLM_URL=http://host.docker.internal:$INFERENCE_PORT \
+  --env SAFETY_MODEL=$SAFETY_MODEL \
+  --env VLLM_SAFETY_URL=http://host.docker.internal:$SAFETY_PORT
+```
+
+
+### Via Conda
+
+Make sure you have done `pip install llama-stack` and have the Llama Stack CLI available.
+
+```bash
+llama stack build --template remote-vllm --image-type conda
+llama stack run ./run.yaml \
+  --port 5001 \
+  --env INFERENCE_MODEL=$INFERENCE_MODEL \
+  --env VLLM_URL=http://127.0.0.1:$INFERENCE_PORT
+```
+
+If you are using Llama Stack Safety / Shield APIs, use:
+
+```bash
+llama stack run ./run-with-safety.yaml \
+  --port 5001 \
+  --env INFERENCE_MODEL=$INFERENCE_MODEL \
+  --env VLLM_URL=http://127.0.0.1:$INFERENCE_PORT \
+  --env SAFETY_MODEL=$SAFETY_MODEL \
+  --env VLLM_SAFETY_URL=http://127.0.0.1:$SAFETY_PORT
+```