Added command to download backup from s3 and restore db from backup

Hi Ed 

This PR adds three new commands to the console 
1. download backup from s3 
2. restore db from backup 
3. delete downloaded backup 

In the cli these are combined into one command which restores the db from the latest backup which can be found on s3.  All files are stored in a temp directory which is deleted afterwards. 

I followed your lead and did not include any cs related information. Everything is configurable via console input or via parameters in the cli. 

I've added "Are you sure" dialogs before actually deleting a backup or restoring a db