Move admin/tos to src/Module

- Add Module\Admin\Tos class
- Add route for admin/tos
- Add admin aside menu entry
- Remove admin_page_tos and admin_page_tos_post from mod/admin.php

src/App/Router.php

@@ -121,6 +121,8 @@ class Router
 		$this->routeCollector->addGroup('/admin', function (RouteCollector $collector) {
 			$collector->addRoute(['GET']        , '[/]'                     , Module\Admin\Summary::class);
 			$collector->addRoute(['GET']        , '/federation'             , Module\Admin\Federation::class);
+
+			$collector->addRoute(['GET', 'POST'], '/tos'                    , Module\Admin\Tos::class);
 		});
 	}