Use auto-updating, natively hoverable, localized time elements (#23988)

- Added [GitHub's `relative-time` element](https://github.com/github/relative-time-element)
- Converted all formatted timestamps to use this element
- No more flashes of unstyled content around time elements
- These elements are localized using the `lang` property of the HTML file
- Relative (e.g. the activities in the dashboard) and duration (e.g.
server uptime in the admin page) time elements are auto-updated to keep
up with the current time without refreshing the page
- Code that is not needed anymore such as `formatting.js` and parts of `since.go` have been deleted

Replaces #21440
Follows #22861

## Screenshots

### Localized

![image](https://user-images.githubusercontent.com/20454870/230775041-f0af4fda-8f6b-46d3-b8e3-d340c791a50c.png)

![image](https://user-images.githubusercontent.com/20454870/230673393-931415a9-5729-4ac3-9a89-c0fb5fbeeeb7.png)

### Tooltips

#### Native for dates

![image](https://user-images.githubusercontent.com/20454870/230797525-1fa0a854-83e3-484c-9da5-9425ab6528a3.png)

#### Interactive for relative

![image](https://user-images.githubusercontent.com/115237/230796860-51e1d640-c820-4a34-ba2e-39087020626a.png)

### Auto-update

![rec](https://user-images.githubusercontent.com/20454870/230672159-37480d8f-435a-43e9-a2b0-44073351c805.gif)

---------

Signed-off-by: Yarden Shoham <git@yardenshoham.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: delvh <dev.lh@web.de>

1 files changed, 0 insertions, 31 deletions

diff --git a/web_src/js/features/formatting.js b/web_src/js/features/formatting.js
deleted file mode 100644
index 5590ba44d1..0000000000
--- a/web_src/js/features/formatting.js
+++ /dev/null
@@ -1,31 +0,0 @@
-const {lang} = document.documentElement;
-const dateFormatter = new Intl.DateTimeFormat(lang, {year: 'numeric', month: 'long', day: 'numeric'});
-const shortDateFormatter = new Intl.DateTimeFormat(lang, {year: 'numeric', month: 'short', day: 'numeric'});
-const dateTimeFormatter = new Intl.DateTimeFormat(lang, {year: 'numeric', month: 'short', day: 'numeric', hour: 'numeric', minute: 'numeric', second: 'numeric'});
-
-export function initFormattingReplacements() {
-  // for each <time></time> tag, if it has the data-format attribute, format
-  // the text according to the user's chosen locale and formatter.
-  formatAllTimeElements();
-}
-
-function formatAllTimeElements() {
-  const timeElements = document.querySelectorAll('time[data-format]');
-  for (const timeElement of timeElements) {
-    const formatter = getFormatter(timeElement.dataset.format);
-    timeElement.textContent = formatter.format(new Date(timeElement.dateTime));
-  }
-}
-
-function getFormatter(format) {
-  switch (format) {
-    case 'date':
-      return dateFormatter;
-    case 'short-date':
-      return shortDateFormatter;
-    case 'date-time':
-      return dateTimeFormatter;
-    default:
-      throw new Error('Unknown format');
-  }
-}