feat(eval api): (2.2/n) delete eval / scoring / scoring_fn apis (#1700)

# What does this PR do?
- To make it easier, delete existing `eval/scoring/scoring_function`
apis. There will be a bunch of broken impls here. The sequence is:
1. migrate benchmark graders
2. clean up existing scoring functions

- Add a skeleton evaluation impl to make tests pass. 

## Test Plan
tested in following PRs

[//]: # (## Documentation)

llama_stack/providers/registry/evaluation.py

@@ -0,0 +1,36 @@
+# 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 typing import List
+
+from llama_stack.providers.datatypes import Api, InlineProviderSpec, ProviderSpec
+from llama_stack.providers.utils.kvstore import kvstore_dependencies
+
+
+def available_providers() -> List[ProviderSpec]:
+    return [
+        InlineProviderSpec(
+            api=Api.evaluation,
+            provider_type="inline::meta-reference",
+            pip_packages=[
+                "matplotlib",
+                "pillow",
+                "pandas",
+                "scikit-learn",
+            ]
+            + kvstore_dependencies(),
+            module="llama_stack.providers.inline.evaluation.meta_reference",
+            config_class="llama_stack.providers.inline.evaluation.meta_reference.MetaReferenceEvaluationImplConfig",
+            api_dependencies=[
+                Api.inference,
+                Api.safety,
+                Api.vector_io,
+                Api.vector_dbs,
+                Api.tool_runtime,
+                Api.tool_groups,
+            ],
+        ),
+    ]