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/inline/safety/meta_reference/config.py

@@ -1,48 +0,0 @@
-# Copyright (c) Meta Platforms, Inc. and affiliates.
-# All rights reserved.
-#
-# This source code is licensed under the terms described in the LICENSE file in
-# the root directory of this source tree.
-
-from enum import Enum
-from typing import List, Optional
-
-from llama_models.sku_list import CoreModelId, safety_models
-
-from pydantic import BaseModel, field_validator
-
-
-class PromptGuardType(Enum):
-    injection = "injection"
-    jailbreak = "jailbreak"
-
-
-class LlamaGuardShieldConfig(BaseModel):
-    model: str = "Llama-Guard-3-1B"
-    excluded_categories: List[str] = []
-
-    @field_validator("model")
-    @classmethod
-    def validate_model(cls, model: str) -> str:
-        permitted_models = [
-            m.descriptor()
-            for m in safety_models()
-            if (
-                m.core_model_id
-                in {
-                    CoreModelId.llama_guard_3_8b,
-                    CoreModelId.llama_guard_3_1b,
-                    CoreModelId.llama_guard_3_11b_vision,
-                }
-            )
-        ]
-        if model not in permitted_models:
-            raise ValueError(
-                f"Invalid model: {model}. Must be one of {permitted_models}"
-            )
-        return model
-
-
-class SafetyConfig(BaseModel):
-    llama_guard_shield: Optional[LlamaGuardShieldConfig] = None
-    enable_prompt_guard: Optional[bool] = False