Upgrade knockoutjs and select2

[willgearty]

These two javascript packages (which we store locally in /esp/public/media/scripts/) are many years behind and should be updated (to match our updated jQuery version from 2021). As far as I can tell, we only use these packages for the two-phase class lottery (side note, it's possible this module could use a facelift and we might not need these packages anymore).

https://knockoutjs.com/ - https://github.com/knockout/knockout
https://select2.org/ - https://github.com/select2/select2/releases