feat(eval api): (2.3/n) remove scoring / eval impls + benchmarks (#1766)

# What does this PR do?
- Remove `/eval` and `/scoring` impls
- Clean up benchmarks. The benchmarks exists in the `llama-stack-evals`
repo.
- Rest of grading functions will be added in follow up PR. 

[//]: # (If resolving an issue, uncomment and update the line below)
[//]: # (Closes #[issue-number])

## Test Plan
- CI

[//]: # (## Documentation)

distributions/dependencies.json

@@ -426,38 +426,6 @@
     "transformers",
     "uvicorn"
   ],
-  "open-benchmark": [
-    "aiosqlite",
-    "blobfile",
-    "chardet",
-    "chromadb-client",
-    "datasets",
-    "fastapi",
-    "fire",
-    "httpx",
-    "litellm",
-    "matplotlib",
-    "mcp",
-    "nltk",
-    "numpy",
-    "opentelemetry-exporter-otlp-proto-http",
-    "opentelemetry-sdk",
-    "pandas",
-    "pillow",
-    "psycopg2-binary",
-    "pymongo",
-    "pypdf",
-    "redis",
-    "requests",
-    "scikit-learn",
-    "scipy",
-    "sentencepiece",
-    "sqlite-vec",
-    "together",
-    "tqdm",
-    "transformers",
-    "uvicorn"
-  ],
   "passthrough": [
     "aiosqlite",
     "blobfile",