Components/Cockpit: add a not ready component

Add a component to display when the osbuild-composer socket
is not running. We could potentially try start the socket
in the future when clicking the button, rather than re-directing
to the cockpit services plugin.

src/Components/Cockpit/NotReady.tsx

@@ -0,0 +1,47 @@
+import React from 'react';
+
+import {
+  Button,
+  EmptyState,
+  EmptyStateActions,
+  EmptyStateBody,
+  EmptyStateFooter,
+  EmptyStateIcon,
+  EmptyStateVariant,
+  Title,
+} from '@patternfly/react-core';
+import { CubesIcon } from '@patternfly/react-icons';
+import cockpit from 'cockpit';
+
+export const NotReady = ({ enabled }: { enabled: boolean }) => {
+  return (
+    <EmptyState variant={EmptyStateVariant.xl}>
+      <EmptyStateIcon icon={CubesIcon} />
+      <Title headingLevel="h4" size="lg">
+        OSBuild Composer is not {enabled ? 'started' : 'enabled'}
+      </Title>
+      <EmptyStateBody />
+      <EmptyStateFooter>
+        <EmptyStateActions>
+          <Button
+            variant="primary"
+            onClick={(event) => {
+              event.preventDefault();
+              cockpit
+                .spawn(
+                  ['systemctl', 'enable', '--now', 'osbuild-composer.socket'],
+                  {
+                    superuser: 'require',
+                    err: 'message',
+                  }
+                )
+                .then(() => window.location.reload());
+            }}
+          >
+            Start socket
+          </Button>
+        </EmptyStateActions>
+      </EmptyStateFooter>
+    </EmptyState>
+  );
+};