Display ui time with customize time location (#7792)

* display ui time with customize time location

* fix lint

* rename UILocation to DefaultUILocation

* move time related functions to modules/timeutil

* fix tests

* fix tests

* fix build

* fix swagger

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -503,8 +503,12 @@ Two special environment variables are passed to the render command:
 - `GITEA_PREFIX_SRC`, which contains the current URL prefix in the `src` path tree. To be used as prefix for links.
 - `GITEA_PREFIX_RAW`, which contains the current URL prefix in the `raw` path tree. To be used as prefix for image paths.
 
+## Time (`time`)
+- `FORMAT`: Time format to diplay on UI. i.e. RFC1123 or 2006-01-02 15:04:05
+- `DEFAULT_UI_LOCATION`: Default location of time on the UI, so that we can display correct user's time on UI. i.e. Shanghai/Asia
+
 ## Other (`other`)
 
 - `SHOW_FOOTER_BRANDING`: **false**: Show Gitea branding in the footer.
 - `SHOW_FOOTER_VERSION`: **true**: Show Gitea version information in the footer.
-- `SHOW_FOOTER_TEMPLATE_LOAD_TIME`: **true**: Show time of template execution in the footer.
+- `SHOW_FOOTER_TEMPLATE_LOAD_TIME`: **true**: Show time of template execution in the footer.

docs/content/doc/advanced/config-cheat-sheet.zh-cn.md

@@ -237,7 +237,9 @@ IS_INPUT_FILE = false
 - RENDER_COMMAND: 工具的命令行命令及参数。
 - IS_INPUT_FILE: 输入方式是最后一个参数为文件路径还是从标准输入读取。
 
-
+## Time (`time`)
+- `FORMAT`: 显示在界面上的时间格式。比如： RFC1123 或者 2006-01-02 15:04:05
+- `DEFAULT_UI_LOCATION`: 默认显示在界面上的时区，默认为本地时区。比如： Asia/Shanghai
 
 ## Other (`other`)