Feature: Install widgets into a new directory for versioning and cache busting

[iturgeon]

When widgets get installed now, they just overwrite the old files in place.

We should install them into a new directory for 2 purposes: keeping a short history (and supporting people currently playing an older version), and (the primary reason for this issue) busting CDN cache when a new version is deployed.

So, installing a widget would create a new directory close to what it does now: From $static/widget/4-crossword to $static/widget/4-crossword-fx3k29

The play iframe would then point to something like $static/widget/4-crossword-fx3k29/player.html

• [ ] create a new directory during install.
• [ ] Determine what to use as a directory name, thinking about hashids or shortids
• [ ] Determine what to do about the score module (always use newest or try to use the one associated w/ the version you started playing)
• [ ] keep the last 5 (maybe configurable) versions in place, deleting older ones.
• [ ] make sure starting to play a new widget uses the newest files

[iturgeon]

Adding some ideas from a duplicate issue here:

Agree - my thoughts were to add a randomly chosen directory into the widget url - perhaps id-widget/player.html -> id-widget/dk20#K/player.html If we know what version the widget is - we could use that instead id-widget/player.html -> id-widget/v2.0.1/player.html

[iturgeon]

another idea was introduced over on #1169 where this would be implemented in the MDK - causing the mdk to add the widget version or cache-busting info to the .wigt file output.