Prevent Firefox from using apple-touch-icon (#10402)

* Prevent Firefox from using apple-touch-icon

The opaque background does not work well in Firefox which uses the icon
as a "rich icon". Prevent this by not specifying it in HTML. Real Apple
devices will still request the icon on the static path.

Fixes: https://github.com/go-gitea/gitea/issues/10394

Also adjust gitignore so app.ini.sample becomes searchable and fixed a
variable name in app.ini.sample.

* fix gitignore

routers/routes/routes.go

@@ -1002,6 +1002,10 @@ func RegisterRoutes(m *macaron.Macaron) {
 		}
 	})
 
+	m.Get("/apple-touch-icon.png", func(ctx *context.Context) {
+		ctx.Redirect(path.Join(setting.StaticURLPrefix, "img/apple-touch-icon.png"), 301)
+	})
+
 	// Progressive Web App
 	m.Get("/manifest.json", templates.JSONRenderer(), func(ctx *context.Context) {
 		ctx.HTML(200, "pwa/manifest_json")