<old>This is based on the searchField from Discover. It's a suggestion from @ngraham and I find it's a great idea.
Note: Because it's based on the searchField from Discover licensed under GPL2-or-later and Kirigami is licensed under LGPL2-or-later, this patch need the authorization from @apol and @ngraham, before landing.</old>
Now it's a generic TextField with the possibility to add a button left and a button right. Also, update the Sidebar example to use this component: