settings: add "tasks" button (advanced)

added a GET /tasks route to list tasks with a description (untranslated,
but this is mostly a dev feature anyway). Loaded in a modal by enabling
advanced settings and pressing the Tasks button at the top (where logs,
backups, restart are). Also added some icons in settings, and removed
some redundant "flex flex-row"s on buttons and reduced the spacing in
those with icons to gap-1.

ts/admin.ts

@@ -74,6 +74,8 @@ window.availableProfiles = window.availableProfiles || [];
     window.modals.matrix = new Modal(document.getElementById("modal-matrix"));
 
     window.modals.logs = new Modal(document.getElementById("modal-logs"));
+    
+    window.modals.tasks = new Modal(document.getElementById("modal-tasks"));
 
     window.modals.backedUp = new Modal(document.getElementById("modal-backed-up"));