chore: reorganize billing related package

controller/group.go

@@ -2,13 +2,13 @@ package controller
 
 import (
 	"github.com/gin-gonic/gin"
-	"github.com/songquanpeng/one-api/relay/billing"
+	billingratio "github.com/songquanpeng/one-api/relay/billing/ratio"
 	"net/http"
 )
 
 func GetGroups(c *gin.Context) {
 	groupNames := make([]string, 0)
-	for groupName := range billing.GroupRatio {
+	for groupName := range billingratio.GroupRatio {
 		groupNames = append(groupNames, groupName)
 	}
 	c.JSON(http.StatusOK, gin.H{