update translations

apps/calendar/l10n/de.php

apps/calendar/l10n/fr.php

apps/calendar/l10n/gl.php

apps/calendar/l10n/it.php

apps/contacts/l10n/ca.php

apps/contacts/l10n/fr.php

apps/contacts/l10n/gl.php

apps/contacts/l10n/it.php

apps/contacts/l10n/sr.php

apps/gallery/l10n/ca.php

apps/gallery/l10n/de.php

apps/gallery/l10n/fr.php

apps/gallery/l10n/gl.php

apps/gallery/l10n/it.php

apps/gallery/l10n/sk_SK.php

apps/gallery/l10n/sr.php

apps/gallery/l10n/zh_CN.php

apps/media/l10n/gl.php

core/l10n/gl.php

core/l10n/it.php