Allow using localized absolute date times within phrases with place holders and localize issue due date events (#24275)

This refactors the `shared/datetime/short|long|full` templates into a
template helper function, which allows us to render absolute date times
within translatable phrases.

- Follows #23988
- The first attempt was in #24055
- This should help #22664 

Changes:
1. Added the `DateTime` template helper that replaces the
`shared/datetime/short|long|full` templates
2. Used find-and-replace with varying regexes to replace the templates
from step 1 (for example, `\{\{template "shared/datetime/(\S+) \(dict
"Datetime" ([^"]+) "Fallback" ([^\)]+\)?) ?\)?\}\}` -> `{{DateTime "$1
$2 $3}}`)
3. Used the new `DateTime` helper in the issue due date timestamp
rendering

# Before

![image](https://user-images.githubusercontent.com/20454870/233791256-b454c455-aca0-4b76-b300-7866c7bd529e.png)

# After

![image](https://user-images.githubusercontent.com/20454870/233790809-c4913355-2822-4657-bb29-2298deb6d4b3.png)

---------

Signed-off-by: Yarden Shoham <git@yardenshoham.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/admin/cron.tmpl

@@ -21,8 +21,8 @@
 						<td><button type="submit" class="ui green button" name="op" value="{{.Name}}" title="{{$.locale.Tr "admin.dashboard.operation_run"}}">{{svg "octicon-triangle-right"}}</button></td>
 						<td>{{$.locale.Tr (printf "admin.dashboard.%s" .Name)}}</td>
 						<td>{{.Spec}}</td>
-						<td>{{template "shared/datetime/full" (dict "Datetime" (DateFmtLong .Next) "Fallback" (DateFmtLong .Next) )}}</td>
-						<td>{{if gt .Prev.Year 1}}{{template "shared/datetime/full" (dict "Datetime" (DateFmtLong .Prev) "Fallback" (DateFmtLong .Prev) )}}{{else}}N/A{{end}}</td>
+						<td>{{DateTime "full" (DateFmtLong .Next) (DateFmtLong .Next)}}</td>
+						<td>{{if gt .Prev.Year 1}}{{DateTime "full" (DateFmtLong .Prev) (DateFmtLong .Prev)}}{{else}}N/A{{end}}</td>
 						<td>{{.ExecTimes}}</td>
 						<td {{if ne .Status ""}}data-tooltip-content="{{.FormatLastMessage $.locale}}"{{end}} >{{if eq .Status ""}}—{{else if eq .Status "finished"}}{{svg "octicon-check" 16}}{{else}}{{svg "octicon-x" 16}}{{end}}</td>
 					</tr>