Add new alternative reference formats, stored by
the proposed text:reference-language attribute.

This is an implementation of the ODF improvement draft
published in the bug report.

Note: choose Hungarian locale setting to show the
new "Article a/az + Page" etc. reference formats
in dialog window "Fields".

Change-Id: I210d4b9a3e821fb4e45e24643bad9c70b867c89d
Reviewed-on: https://gerrit.libreoffice.org/48944Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>