MRBS 1.12.2 等保2.0二级整改完整提交

包含：登录失败锁定、90天密码有效期、30分钟会话超时、
强制改密、登录审计日志、屏幕水印、企业背景图、
备案信息固定底部、favicon、JS空集合保护、
会话过期体验优化（403 JSON）、display_errors 关闭、
固定 key 根治 Integrity check failed 等全部改动

注意：config.inc.php/.htaccess/.user.ini 含敏感信息，
通过 .gitignore 排除，勿推送到公开仓库。

upgrade/48/post.inc

@@ -0,0 +1,16 @@
+<?php
+namespace MRBS;
+
+$message = "If you have just upgraded to MRBS 1.5.1 or later please " .
+           "note that the config setting '" . '$db_nopersist' . "' has been replaced " .
+           "by '" . '$db_persist' . "'.  The default setting for MRBS is now *not* to " .
+           "use persistent connections.";
+?>
+
+<script>
+//<![CDATA[
+  alert("<?php echo $message?>");
+//]];
+</script>
+
+<?php