made a sticky header for the table

src/pages/Devices.tsx

@@ -735,6 +735,7 @@ export default function Devices() {
       <ResponsiveTable<Device>
         title={<SmartBreadcrumb prependPaths={getGroup() && ["groups", getGroup().id().toString()]} groupName={getGroup() && getGroup().name()} paddingBottom={1}/>}
         subtitle={subtitle}
+        stickyHeader
         rows={devices}
         renderGutter={ isMobile ? gutter : undefined }
         columns={columns}