The homepage of the Unsafe Browser cannot be translated

Originally created by @sajolida on #15461 (Redmine)

Due to #14962 (closed), we had to apply a temporary workaround: 08259afa, a02aafef, 527b2c37.

But that’s problematic: translators can’t easily update/fix translations in PO files for that web page, and newly enabled languages don’t get a translated page (e.g. we’ve enabled Spanish and guess what? of course nobody thought of manually translating that HTML file).

So, we should:

• either do something clever to avoid using markup/CSS that won’t render due to #14962 (closed) (can we use a custom page template? last time I check we could not) and then reintegrate this HTML file into our ikiwiki+po setup to make that page translatable again; likely that won’t work so let’s not spend too much time of it before switching to:
• or keep most of the current hacks, treat that web page as something outside of ikiwiki’s scope, and make it translatable via Transifex:
  • move the source page out of wiki/src
  • integrate it with our non-ikiwiki translation setup (po/, refresh-translations, etc.)
  • replace fixup_14962_workaround with something that copies the generated translated pages to config/chroot_local-includes/usr/share/doc/tails/website/misc
• or find a nicer, cheap enough solution to this problem :)

For future plans, see #14962 (comment 30357) and follow-ups.

Feature Branch: https://0xacab.org/Hefee/tails/tree/bugfix/15461-translate-unsafe-browser-homepage

Related issues

• Related to #14962 (closed)
• Blocks tails/accounting#15139