Implement fingerprinting on assets for more reliable deploys

[dylancashman]

We've run into issues in the past with caching, when we change out the code and it takes some time for the users to have their caches expire and pick up the new assets. The solution to this is probably to use Webpack fingerprinting.

This is especially a problem around the actual conference date when we are making many frequent updates. We also need to implement this on the virtual website: ieee-vgtc/vis-virtual-website#103

[Zarnosch]

We can use a flask extension for that: https://github.com/nickjj/flask-static-digest