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/editor-page/document-bar/permissions/permission-section-users.tsx

@@ -0,0 +1,50 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+import React, { Fragment, useCallback, useMemo } from 'react'
+import { Trans, useTranslation } from 'react-i18next'
+import { useApplicationState } from '../../../../hooks/common/use-application-state'
+import { PermissionEntryUser } from './permission-entry-user'
+import { PermissionAddEntryField } from './permission-add-entry-field'
+import { setUserPermission } from '../../../../api/permissions'
+import { setNotePermissionsFromServer } from '../../../../redux/note-details/methods'
+import { useUiNotifications } from '../../../notifications/ui-notification-boundary'
+
+/**
+ * Section of the permission modal for managing user access to the note.
+ */
+export const PermissionSectionUsers: React.FC = () => {
+  useTranslation()
+  const userPermissions = useApplicationState((state) => state.noteDetails.permissions.sharedToUsers)
+  const noteId = useApplicationState((state) => state.noteDetails.primaryAddress)
+  const { showErrorNotification } = useUiNotifications()
+
+  const userEntries = useMemo(() => {
+    return userPermissions.map((entry) => <PermissionEntryUser key={entry.username} entry={entry} />)
+  }, [userPermissions])
+
+  const onAddEntry = useCallback(
+    (username: string) => {
+      setUserPermission(noteId, username, false)
+        .then((updatedPermissions) => {
+          setNotePermissionsFromServer(updatedPermissions)
+        })
+        .catch(showErrorNotification('editor.modal.permissions.error'))
+    },
+    [noteId, showErrorNotification]
+  )
+
+  return (
+    <Fragment>
+      <h5 className={'my-3'}>
+        <Trans i18nKey={'editor.modal.permissions.sharedWithUsers'} />
+      </h5>
+      <ul className={'list-group'}>
+        {userEntries}
+        <PermissionAddEntryField onAddEntry={onAddEntry} i18nKey={'editor.modal.permissions.addUser'} />
+      </ul>
+    </Fragment>
+  )
+}