[trunk] - language - update vi_VN - Tiếng Việt - Vietnamese thanks to Em Ku

git-svn-id: http://piwigo.org/svn/trunk@23120 68402e56-0260-453c-a942-63ccdbb3a9ee
bug:2890
new layout finished: ie7 compat, dynamic, rounded corners...
the 2 "Manage..." options has been deleted

git-svn-id: http://piwigo.org/svn/trunk@23121 68402e56-0260-453c-a942-63ccdbb3a9ee