Add automated update drush function

Have it do the following:

1. Check if the last automated update failed, if not, continue
2. Check if there are any available updates
3. Set the site offline message
4. Create an archive backup
5. Put the site into offline mode
6. Download the updates
7. Run the update scripts
8. Re-Patch any projects
9. Run updatedb once again (in case the patches include schema changes)
10. Put the site back into online mode
11. Report to dropfort the results of the update

If at any point the update throws an error, restore the archive backup and set the "failed auto-update" flag to true (preventing future attempts).