perf: 优化系统用户，支持用户设置临时密码

perf: 优化rdp file下载

perf: 修改密码途观选项

perf: 优化api获取

apps/assets/models/base.py

@@ -11,8 +11,7 @@ from django.db import models
 from django.utils.translation import ugettext_lazy as _
 from django.conf import settings
 
-from common.db.models import ChoiceSet
-from common.utils import random_string
+from common.utils import random_string, signer
 from common.utils import (
     ssh_key_string_to_obj, ssh_key_gen, get_logger, lazyproperty
 )