Create update feature for reproducibility

[acrinklaw]

Per Leonard Nettey at MIT:
I think an automatic check for an update would be very helpful. Then a user could decide whether or not to update (e.g. if you want to be sure you get the same output for a given input to ensure reproducibility, you don’t update).

Based on this, we should add a way to automatically check for updates. Additionally, add an option to create a dated archive of the current state of the IEDB, in order to facilitate reproducibility. Then a user could select an option to restore from archived backup of old data if they need to go back and run some analysis. This should be facilitated by the tool, rather than requiring the user to go out of their way to do so

[acrinklaw]

Added update.sh script to create data archive and download latest release