[Evals API][3/n] scoring_functions / scoring meta-reference implementations (#296)

* wip

* dataset validation

* test_scoring

* cleanup

* clean up test

* comments

* error checking

* dataset client

* test client:

* datasetio client

* clean up

* basic scoring function works

* scorer wip

* equality scorer

* score batch impl

* score batch

* update scoring test

* refactor

* validate scorer input

* address comments

* add all rows scores to ScoringResult

* bugfix

* scoring function def rename

llama_stack/distribution/routers/__init__.py

@@ -11,6 +11,7 @@ from .routing_tables import (
     DatasetsRoutingTable,
     MemoryBanksRoutingTable,
     ModelsRoutingTable,
+    ScoringFunctionsRoutingTable,
     ShieldsRoutingTable,
 )
 
@@ -25,7 +26,9 @@ async def get_routing_table_impl(
         "models": ModelsRoutingTable,
         "shields": ShieldsRoutingTable,
         "datasets": DatasetsRoutingTable,
+        "scoring_functions": ScoringFunctionsRoutingTable,
     }
+
     if api.value not in api_to_tables:
         raise ValueError(f"API {api.value} not found in router map")
 
@@ -35,13 +38,20 @@ async def get_routing_table_impl(
 
 
 async def get_auto_router_impl(api: Api, routing_table: RoutingTable, _deps) -> Any:
-    from .routers import DatasetIORouter, InferenceRouter, MemoryRouter, SafetyRouter
+    from .routers import (
+        DatasetIORouter,
+        InferenceRouter,
+        MemoryRouter,
+        SafetyRouter,
+        ScoringRouter,
+    )
 
     api_to_routers = {
         "memory": MemoryRouter,
         "inference": InferenceRouter,
         "safety": SafetyRouter,
         "datasetio": DatasetIORouter,
+        "scoring": ScoringRouter,
     }
     if api.value not in api_to_routers:
         raise ValueError(f"API {api.value} not found in router map")