Remember login for a month by default (#30150)

Previously, the default was a week.
As most instances don't set the setting, this leads to a bad user
experience by default.

## ⚠️ Breaking

If your instance requires a high level of security,
you may want to set `[security].LOGIN_REMEMBER_DAYS` so that logins are
not valid as long.

---------

Co-authored-by: Jason Song <i@wolfogre.com>
(cherry picked from commit 0d5abe3454c73f11d90d2809af0949a0e0636c22)

docs/content/administration/config-cheat-sheet.en-us.md

@@ -528,7 +528,7 @@ And the following unique queues:
 - `INSTALL_LOCK`: **false**: Controls access to the installation page. When set to "true", the installation page is not accessible.
 - `SECRET_KEY`: **\<random at every install\>**: Global secret key. This key is VERY IMPORTANT, if you lost it, the data encrypted by it (like 2FA secret) can't be decrypted anymore.
 - `SECRET_KEY_URI`: **_empty_**: Instead of defining SECRET_KEY, this option can be used to use the key stored in a file (example value: `file:/etc/gitea/secret_key`). It shouldn't be lost like SECRET_KEY.
-- `LOGIN_REMEMBER_DAYS`: **7**: Cookie lifetime, in days.
+- `LOGIN_REMEMBER_DAYS`: **31**: How long to remember that a user is logged in before requiring relogin (in days).
 - `COOKIE_REMEMBER_NAME`: **gitea\_incredible**: Name of cookie used to store authentication
    information.
 - `REVERSE_PROXY_AUTHENTICATION_USER`: **X-WEBAUTH-USER**: Header name for reverse proxy

docs/content/administration/config-cheat-sheet.zh-cn.md

@@ -507,7 +507,7 @@ Gitea 创建以下非唯一队列：
 - `INSTALL_LOCK`: **false**：控制是否能够访问安装向导页面，设置为 `true` 则禁止访问安装向导页面。
 - `SECRET_KEY`: **\<每次安装时随机生成\>**：全局服务器安全密钥。这个密钥非常重要，如果丢失将无法解密加密的数据（例如 2FA）。
 - `SECRET_KEY_URI`: **_empty_**：与定义 `SECRET_KEY` 不同，此选项可用于使用存储在文件中的密钥（示例值：`file:/etc/gitea/secret_key`）。它不应该像 `SECRET_KEY` 一样容易丢失。
-- `LOGIN_REMEMBER_DAYS`: **7**：Cookie 保存时间，单位为天。
+- `LOGIN_REMEMBER_DAYS`: **31**：在要求重新登录之前，记住用户的登录状态多长时间（以天为单位）。
 - `COOKIE_REMEMBER_NAME`: **gitea\_incredible**：保存自动登录信息的 Cookie 名称。
 - `REVERSE_PROXY_AUTHENTICATION_USER`: **X-WEBAUTH-USER**：反向代理认证的 HTTP 头部名称，用于提供用户信息。
 - `REVERSE_PROXY_AUTHENTICATION_EMAIL`: **X-WEBAUTH-EMAIL**：反向代理认证的 HTTP 头部名称，用于提供邮箱信息。