refactor: migrate group ratio and user usable groups logic to new setting package

- Replaced references to common.GroupRatio and common.UserUsableGroups with corresponding functions from the new setting package across multiple controllers and services.
- Introduced new setting functions for managing group ratios and user usable groups, enhancing code organization and maintainability.
- Updated related functions to ensure consistent behavior with the new setting package integration.

setting/user_usable_group.go

@@ -0,0 +1,47 @@
+package setting
+
+import (
+	"encoding/json"
+	"one-api/common"
+)
+
+var UserUsableGroups = map[string]string{
+	"default": "默认分组",
+	"vip":     "vip分组",
+}
+
+func UserUsableGroups2JSONString() string {
+	jsonBytes, err := json.Marshal(UserUsableGroups)
+	if err != nil {
+		common.SysError("error marshalling user groups: " + err.Error())
+	}
+	return string(jsonBytes)
+}
+
+func UpdateUserUsableGroupsByJSONString(jsonStr string) error {
+	UserUsableGroups = make(map[string]string)
+	return json.Unmarshal([]byte(jsonStr), &UserUsableGroups)
+}
+
+func GetUserUsableGroups(userGroup string) map[string]string {
+	if userGroup == "" {
+		// 如果userGroup为空，返回UserUsableGroups
+		return UserUsableGroups
+	}
+	// 如果userGroup不在UserUsableGroups中，返回UserUsableGroups + userGroup
+	if _, ok := UserUsableGroups[userGroup]; !ok {
+		appendUserUsableGroups := make(map[string]string)
+		for k, v := range UserUsableGroups {
+			appendUserUsableGroups[k] = v
+		}
+		appendUserUsableGroups[userGroup] = "用户分组"
+		return appendUserUsableGroups
+	}
+	// 如果userGroup在UserUsableGroups中，返回UserUsableGroups
+	return UserUsableGroups
+}
+
+func GroupInUserUsableGroups(groupName string) bool {
+	_, ok := UserUsableGroups[groupName]
+	return ok
+}