* (bug 10677) Add link to the file description page on the shared repository

* (bug 10677) Add link to the file description page on the shared repository
The existing message 'sharedupload' does not has a link to the shared repository. A lot of WMF projects has modified it locally but for their content language only.
That means, all users with another user language does not profit from the modification.
Compare http://en.wikipedia.org/wiki/Image:test.jpg?uselang=en and http://en.wikipedia.org/wiki/Image:test.jpg?uselang=eo
New message 'shareduploadwiki-desc' introduced. This can be set to '-' by local sysops to suppress the message if 'sharedupload' has a link already.