Split safety into (llama-guard, prompt-guard, code-scanner) (#400)

Splits the meta-reference safety implementation into three distinct providers:

- inline::llama-guard
- inline::prompt-guard
- inline::code-scanner

Note that this PR is a backward incompatible change to the llama stack server. I have added deprecation_error field to ProviderSpec -- the server reads it and immediately barfs. This is used to direct the user with a specific message on what action to perform. An automagical "config upgrade" is a bit too much work to implement right now :/

(Note that we will be gradually prefixing all inline providers with inline:: -- I am only doing this for this set of new providers because otherwise existing configuration files will break even more badly.)

llama_stack/providers/tests/inference/fixtures.py

@@ -65,7 +65,6 @@ def inference_ollama(inference_model) -> ProviderFixture:
     inference_model = (
         [inference_model] if isinstance(inference_model, str) else inference_model
     )
-    print("!!!", inference_model)
     if "Llama3.1-8B-Instruct" in inference_model:
         pytest.skip("Ollama only supports Llama3.2-3B-Instruct for testing")
 
@@ -162,9 +161,11 @@ async def inference_stack(request, inference_model):
         inference_fixture.provider_data,
     )
 
+    provider_id = inference_fixture.providers[0].provider_id
+    print(f"Registering model {inference_model} with provider {provider_id}")
     await impls[Api.models].register_model(
         model_id=inference_model,
-        provider_model_id=inference_fixture.providers[0].provider_id,
+        provider_id=provider_id,
     )
 
     return (impls[Api.inference], impls[Api.models])