Allow package cleanup from admin page (#25307)

Until now expired package data gets deleted daily by a cronjob. The
admin page shows the size of all packages and the size of unreferenced
data. The users (#25035, #20631) expect the deletion of this data if
they run the cronjob from the admin page but the job only deletes data
older than 24h.

This PR adds a new button which deletes all expired data.

![grafik](https://github.com/go-gitea/gitea/assets/1666336/b3e35d73-9496-4fa7-a20c-e5d30b1f6850)

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Co-authored-by: silverwind <me@silverwind.io>

templates/admin/packages/list.tmpl

@@ -4,6 +4,12 @@
 			{{.locale.Tr "admin.packages.package_manage_panel"}} ({{.locale.Tr "admin.total" .TotalCount}},
 			{{.locale.Tr "admin.packages.total_size" (FileSize .TotalBlobSize)}},
 			{{.locale.Tr "admin.packages.unreferenced_size" (FileSize .TotalUnreferencedBlobSize)}})
+			<div class="ui right">
+				<form method="post" action="/admin/packages/cleanup">
+					{{.CsrfTokenHtml}}
+					<button class="ui primary tiny button">{{.locale.Tr "admin.packages.cleanup"}}</button>
+				</form>
+			</div>
 		</h4>
 		<div class="ui attached segment">
 			<form class="ui form ignore-dirty">