Newsletters HTML editor, Modal confirmation, CDN images

- Modal confirmation replace with something better open-classifieds/openclassifieds2#963
- CDN images open-classifieds/openclassifieds2#961
- Fixes newsletters editor usage of HTML editor not BBCODE open-classifieds/openclassifieds2#981
In that case we need to redo the naming of the files...I know sucks but is the best, we can not be doing HTTP requests to get the images all the time, I think is the best solution, what do you think?