when deciding to create a new folder on server: check permissions

when deciding to create a new folder on server: check permissions

sometime we need to create a folder on server because some local files
or folders modifications would be lost without that

in that case instead of locally deleting teh folder, we create it back
on server

when doing that, it is important to check the remote permissions such
that we do not try to create a folder in a read-only folder on server

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>