Record model and cost when reporting logs (#136)

* Rename prompt and completion tokens to input and output tokens

* Add getUsage function

* Record model and cost when reporting log

* Remove unused imports

* Move UsageGraph to its own component

* Standardize model response fields

* Fix types

app/src/server/api/routers/experiments.router.ts

@@ -227,7 +227,7 @@ export const experimentsRouter = createTRPCRouter({
             ...modelResponseData,
             id: newModelResponseId,
             scenarioVariantCellId: newCellId,
-            output: (modelResponse.output as Prisma.InputJsonValue) ?? undefined,
+            respPayload: (modelResponse.respPayload as Prisma.InputJsonValue) ?? undefined,
           });
           for (const evaluation of outputEvaluations) {
             outputEvaluationsToCreate.push({