Overhaul demos directory: cleanup, restructure, and standardize configs (#760)

demos/getting_started/llm_gateway/config.yaml

@@ -0,0 +1,51 @@
+version: v0.3.0
+
+listeners:
+  - type: model
+    name: model_1
+    address: 0.0.0.0
+    port: 12000
+    max_retries: 3
+
+model_providers:
+
+  - access_key: $OPENAI_API_KEY
+    model: openai/gpt-4o-mini
+
+  - access_key: $OPENAI_API_KEY
+    model: openai/gpt-4.1
+
+  - access_key: $OPENAI_API_KEY
+    model: openai/gpt-4o
+    default: true
+
+  - access_key: $MISTRAL_API_KEY
+    model: mistral/ministral-3b-latest
+
+  - access_key: $ANTHROPIC_API_KEY
+    model: anthropic/claude-3-7-sonnet-latest
+
+  - access_key: $ANTHROPIC_API_KEY
+    model: anthropic/claude-sonnet-4-0
+
+  - access_key: $DEEPSEEK_API_KEY
+    model: deepseek/deepseek-reasoner
+
+  - access_key: $GROQ_API_KEY
+    model: groq/llama-3.1-8b-instant
+
+  - access_key: $GEMINI_API_KEY
+    model: gemini/gemini-1.5-pro-latest
+
+  - model: xai/grok-4-latest
+    access_key: $GROK_API_KEY
+
+  - model: together_ai/openai/gpt-oss-20b
+    access_key: $TOGETHER_API_KEY
+
+  - model: custom/test-model
+    base_url: http://host.docker.internal:11223
+    provider_interface: openai
+
+tracing:
+  random_sampling: 100