Add template linting via djlint (#25212)

So I found this [linter](https://github.com/Riverside-Healthcare/djlint)
which features a mode for go templates, so I gave it a try and it did
find a number of valid issue, like unbalanced tags etc. It also has a
number of bugs, I had to disable/workaround many issues.

Given that this linter is written in python, this does add a dependency
on `python` >= 3.8 and `poetry` to the development environment to be
able to run this linter locally.

- `e.g.` prefixes on placeholders are removed because the linter had a
false-positive on `placeholder="e.g. cn=Search"` for the `attr=value`
syntax and it's not ideal anyways to write `e.g.` into a placeholder
because a placeholder is meant to hold a sample value.
- In `templates/repo/settings/options.tmpl` I simplified the logic to
not conditionally create opening tags without closing tags because this
stuff confuses the linter (and possibly the reader as well).

templates/admin/queue.tmpl

@@ -23,7 +23,7 @@
 				<td>{{$q.GetItemTypeName}}</td>
 				<td>{{$sum := $q.GetWorkerNumber}}{{if lt $sum 0}}-{{else}}{{$sum}}{{end}}</td>
 				<td>{{$sum = $q.GetQueueItemNumber}}{{if lt $sum 0}}-{{else}}{{$sum}}{{end}}</td>
-				<td><a href="{{$.Link}}/{{$qid}}" class="button">{{if lt $sum 0}}{{$.locale.Tr "admin.monitor.queue.review"}}{{else}}{{$.locale.Tr "admin.monitor.queue.review_add"}}{{end}}</a>
+				<td><a href="{{$.Link}}/{{$qid}}" class="button">{{if lt $sum 0}}{{$.locale.Tr "admin.monitor.queue.review"}}{{else}}{{$.locale.Tr "admin.monitor.queue.review_add"}}{{end}}</a></td>
 			</tr>
 			{{end}}
 			</tbody>