refactor: backend/service split, channel-based llm flow (#1963)

Refactor: channel based llm flow and services split

---------

Signed-off-by: Dave Lee <dave@gray101.com>

core/http/endpoints/openai/inference.go

@@ -1,55 +0,0 @@
-package openai
-
-import (
-	"github.com/go-skynet/LocalAI/core/backend"
-	"github.com/go-skynet/LocalAI/core/config"
-
-	"github.com/go-skynet/LocalAI/core/schema"
-	model "github.com/go-skynet/LocalAI/pkg/model"
-)
-
-func ComputeChoices(
-	req *schema.OpenAIRequest,
-	predInput string,
-	config *config.BackendConfig,
-	o *config.ApplicationConfig,
-	loader *model.ModelLoader,
-	cb func(string, *[]schema.Choice),
-	tokenCallback func(string, backend.TokenUsage) bool) ([]schema.Choice, backend.TokenUsage, error) {
-	n := req.N // number of completions to return
-	result := []schema.Choice{}
-
-	if n == 0 {
-		n = 1
-	}
-
-	images := []string{}
-	for _, m := range req.Messages {
-		images = append(images, m.StringImages...)
-	}
-
-	// get the model function to call for the result
-	predFunc, err := backend.ModelInference(req.Context, predInput, req.Messages, images, loader, *config, o, tokenCallback)
-	if err != nil {
-		return result, backend.TokenUsage{}, err
-	}
-
-	tokenUsage := backend.TokenUsage{}
-
-	for i := 0; i < n; i++ {
-		prediction, err := predFunc()
-		if err != nil {
-			return result, backend.TokenUsage{}, err
-		}
-
-		tokenUsage.Prompt += prediction.Usage.Prompt
-		tokenUsage.Completion += prediction.Usage.Completion
-
-		finetunedResponse := backend.Finetune(*config, predInput, prediction.Response)
-		cb(finetunedResponse, &result)
-
-		//result = append(result, Choice{Text: prediction})
-
-	}
-	return result, tokenUsage, err
-}