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
Now I see that because of S3 cache, after re-ordering image file names on S3 is still displaying previous image. The same when a category/location/profile icon is changed. Guess we need in some way add a timestamp on every image file name.