Automatic backups with webstudio

if you are self-hosting you could do automatic backups on the database level

otherwise there is an issue for versioning, which means you don't need backups, you will just go back to any version https://github.com/webstudio-is/webstudio/issues/2643

additionally per-project import-export will be possible manually as well once we have done this https://github.com/webstudio-is/webstudio/issues/961