chore(yaml)!: move registered resources to a sub-key (#3861)

**NOTE: this is a backwards incompatible change to the run-configs.**

A small QOL update, but this will prove useful when I do a rename for
"vector_dbs" to "vector_stores" next.

Moves all the `models, shields, ...` keys in run-config under a
`registered_resources` sub-key.

llama_stack/distributions/postgres-demo/run.yaml

@@ -87,27 +87,28 @@ storage:
     conversations:
       table_name: openai_conversations
       backend: sql_default
-models:
-- metadata: {}
-  model_id: ${env.INFERENCE_MODEL}
-  provider_id: vllm-inference
-  model_type: llm
-- metadata:
-    embedding_dimension: 768
-  model_id: nomic-embed-text-v1.5
-  provider_id: sentence-transformers
-  model_type: embedding
-shields:
-- shield_id: meta-llama/Llama-Guard-3-8B
-vector_dbs: []
-datasets: []
-scoring_fns: []
-benchmarks: []
-tool_groups:
-- toolgroup_id: builtin::websearch
-  provider_id: tavily-search
-- toolgroup_id: builtin::rag
-  provider_id: rag-runtime
+registered_resources:
+  models:
+  - metadata: {}
+    model_id: ${env.INFERENCE_MODEL}
+    provider_id: vllm-inference
+    model_type: llm
+  - metadata:
+      embedding_dimension: 768
+    model_id: nomic-embed-text-v1.5
+    provider_id: sentence-transformers
+    model_type: embedding
+  shields:
+  - shield_id: meta-llama/Llama-Guard-3-8B
+  vector_dbs: []
+  datasets: []
+  scoring_fns: []
+  benchmarks: []
+  tool_groups:
+  - toolgroup_id: builtin::websearch
+    provider_id: tavily-search
+  - toolgroup_id: builtin::rag
+    provider_id: rag-runtime
 server:
   port: 8321
 telemetry: