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/templates/nvidia/run.yaml

@@ -3,10 +3,8 @@ image_name: nvidia
 apis:
 - agents
 - datasetio
-- eval
 - inference
 - safety
-- scoring
 - telemetry
 - tool_runtime
 - vector_io
@@ -46,14 +44,6 @@ providers:
       service_name: ${env.OTEL_SERVICE_NAME:llama-stack}
       sinks: ${env.TELEMETRY_SINKS:console,sqlite}
       sqlite_db_path: ${env.SQLITE_DB_PATH:~/.llama/distributions/nvidia/trace_store.db}
-  eval:
-  - provider_id: meta-reference
-    provider_type: inline::meta-reference
-    config:
-      kvstore:
-        type: sqlite
-        namespace: null
-        db_path: ${env.SQLITE_STORE_DIR:~/.llama/distributions/nvidia}/meta_reference_eval.db
   datasetio:
   - provider_id: localfs
     provider_type: inline::localfs
@@ -62,10 +52,6 @@ providers:
         type: sqlite
         namespace: null
         db_path: ${env.SQLITE_STORE_DIR:~/.llama/distributions/nvidia}/localfs_datasetio.db
-  scoring:
-  - provider_id: basic
-    provider_type: inline::basic
-    config: {}
   tool_runtime:
   - provider_id: rag-runtime
     provider_type: inline::rag-runtime
@@ -195,7 +181,6 @@ models:
 shields: []
 vector_dbs: []
 datasets: []
-scoring_fns: []
 benchmarks: []
 tool_groups:
 - toolgroup_id: builtin::rag