feature: add button to open cheatsheet in a new tab

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

frontend/src/pages/cheatsheet.tsx

@@ -0,0 +1,21 @@
+/*
+ * SPDX-FileCopyrightText: 2023 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import { CheatsheetContent } from '../components/editor-page/app-bar/cheatsheet/cheatsheet-content'
+import { useApplyDarkMode } from '../hooks/common/use-apply-dark-mode'
+import type { NextPage } from 'next'
+import { Container } from 'react-bootstrap'
+
+const CheatsheetPage: NextPage = () => {
+  useApplyDarkMode()
+
+  return (
+    <Container>
+      <CheatsheetContent></CheatsheetContent>
+    </Container>
+  )
+}
+
+export default CheatsheetPage