Issue #6587 - Added language self names to strings-app.js

Added language self names in strings-app.js that will be used in favor of localized version for switch language menu.  If it doesn't have a self name it will revert back to the current language translation and if that doesn't exist it will default to the English name.

The ones that didn't have a translation in their specific locale files are:  Italian, Norwegian, Polish, and Russian.  I didn't want to use use Google Translate or some other method for finding out the self names.  I'm hoping that we can get people who are more familiar with the language to fill in these gaps.