More db.DefaultContext refactor (#27265)

Part of #27065

This PR touches functions used in templates. As templates are not static
typed, errors are harder to find, but I hope I catch it all. I think
some tests from other persons do not hurt.

templates/projects/view.tmpl

@@ -68,7 +68,7 @@
 				<div class="project-column-header">
 					<div class="ui large label project-column-title gt-py-2">
 						<div class="ui small circular grey label project-column-issue-count">
-							{{.NumIssues}}
+							{{.NumIssues ctx}}
 						</div>
 						{{.Title}}
 					</div>