Fully i18nize issue page

[sethvargo]

We're going to submit these for translation, so I removed the spanish one for now.

Release Note

Fully internationalize strings on code issue page.

[sethvargo]

/assign @whaught

I moved codescripts into application.js - there we no Go template dependencies. The only change in the javascript is pulling the text "Expired" from a data attribute so it can be available at runtime.

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