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/distribution/start_conda_env.sh

@@ -33,10 +33,33 @@ shift
 port="$1"
 shift
 
+# Process environment variables from --env arguments
+env_vars=""
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        --env)
+
+            if [[ -n "$2" ]]; then
+                # collect environment variables so we can set them after activating the conda env
+                env_vars="$env_vars $2"
+                shift 2
+            else
+                echo -e "${RED}Error: --env requires a KEY=VALUE argument${NC}" >&2
+                exit 1
+            fi
+            ;;
+        *)
+            shift
+            ;;
+    esac
+done
+
 eval "$(conda shell.bash hook)"
 conda deactivate && conda activate "$env_name"
 
-$CONDA_PREFIX/bin/python \
+set -x
+$env_vars \
+  $CONDA_PREFIX/bin/python \
   -m llama_stack.distribution.server.server \
   --yaml_config "$yaml_config" \
   --port "$port" "$@"