CS-5558 - more fixes for TinyMCE localization

The previous fixes for CS-5558 were incomplete; the Italian files were not all present, and the custom plugins did not have all the translation files for the locales we currently support. Some files which we did provide were buggy, causing the plugin GUIs to break. 

Some existing files were for locales that we do not support or are obsolete, so these files have been deleted to clean up those directories.

Also, there was an old typo in the codehighlighting plugin: 

codehighlighting_collapse : "Collapes"

which was fixed while updating the files.