fix: Move content into to frontend directory

Doing this BEFORE the merge prevents a lot of merge conflicts.

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

frontend/src/components/document-read-only-page/document-read-only-page-content.tsx

@@ -0,0 +1,37 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import React, { Fragment } from 'react'
+import { useTranslation } from 'react-i18next'
+import { updateNoteTitleByFirstHeading } from '../../redux/note-details/methods'
+import { DocumentInfobar } from './document-infobar'
+import { RenderIframe } from '../editor-page/renderer-pane/render-iframe'
+import { RendererType } from '../render-page/window-post-message-communicator/rendering-message'
+import { useTrimmedNoteMarkdownContentWithoutFrontmatter } from '../../hooks/common/use-trimmed-note-markdown-content-without-frontmatter'
+import { setRendererStatus } from '../../redux/renderer-status/methods'
+
+/**
+ * Renders the read-only version of a note with a header bar that contains information about the note.
+ */
+export const DocumentReadOnlyPageContent: React.FC = () => {
+  useTranslation()
+
+  const markdownContentLines = useTrimmedNoteMarkdownContentWithoutFrontmatter()
+
+  // TODO Change todo values with real ones as soon as the backend is ready.
+  return (
+    <Fragment>
+      <DocumentInfobar />
+      <RenderIframe
+        frameClasses={'flex-fill h-100 w-100'}
+        markdownContentLines={markdownContentLines}
+        onFirstHeadingChange={updateNoteTitleByFirstHeading}
+        rendererType={RendererType.DOCUMENT}
+        onRendererStatusChange={setRendererStatus}
+      />
+    </Fragment>
+  )
+}