Video management
Depends on #4 (closed).
Constraints:
- when we backup a server, we need all the videos to be backuped, so they need to be saved on the right place (MEDIA_ROOT is on the right place, so no big deal)
- we need to be able to export a blog post and the videos URL to still work
- if possible, we don't want to duplicate the videos if they appear in more than one blog post