Select2 won't load on Turbolinks navigation

[MrSerth]

When localizing CodeHarbor in #1143, we also modified how select2 is loaded (90cf84d). As an unfortunate side effect, however, we are not correctly initializing select2 labels during visits fully handled by Turbolinks.

When navigating a page, Turbolinks aims to reduce page loading times by simply exchanging the document's body. This mostly works fine and indeed is faster than re-parsing all library code on a subsequent page visit. One downside, however, is that the events are not fired as usual. That's happening in this case: Only on a regular, full browser visit, the event select2:locales:loaded is fired. On Turbolinks visits, it is not (since the JavaScript state is also not reinitialized).

Consequentially, the filters shown on the task index page are not necessarily loaded correctly. For example, when switching between Collections and Tasks, the filters are not shown correctly. Only reloading the page without a cache is initializing the filters for me:

Turbolinks.Select2.mov