[BUGFIX] Add missing getter and setter for sys_language_uid and l10n_parent for model link

This change adds the possibility to localize relatedLinks on import

Change-Id: I547b171f0fb718dc1f19f8bc23d431cc51a08d2e
Resolves: #62249
Reviewed-on: http://review.typo3.org/33325
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>