Resource oriented design for shields (#399)

* init

* working bedrock tests

* bedrock test for inference fixes

* use env vars for bedrock guardrail vars

* add register in meta reference

* use correct shield impl in meta ref

* dont add together fixture

* right naming

* minor updates

* improved registration flow

* address feedback

---------

Co-authored-by: Dinesh Yeduguru <dineshyv@fb.com>

llama_stack/apis/resource.py

@@ -0,0 +1,38 @@
+# 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 llama_models.schema_utils import json_schema_type
+from pydantic import BaseModel, Field
+
+
+@json_schema_type
+class ResourceType(Enum):
+    model = "model"
+    shield = "shield"
+    memory_bank = "memory_bank"
+    dataset = "dataset"
+    scoring_function = "scoring_function"
+
+
+class Resource(BaseModel):
+    """Base class for all Llama Stack resources"""
+
+    identifier: str = Field(
+        description="Unique identifier for this resource in llama stack"
+    )
+
+    provider_resource_id: str = Field(
+        description="Unique identifier for this resource in the provider",
+        default=None,
+    )
+
+    provider_id: str = Field(description="ID of the provider that owns this resource")
+
+    type: ResourceType = Field(
+        description="Type of resource (e.g. 'model', 'shield', 'memory_bank', etc.)"
+    )