[Ptitlouis6012]

What this changes

Adds Russian and Dutch to the web installer, next to the two firmware languages in #26. The installer page offers the languages the device speaks, so it should list the same eleven.

The page builds its language menu and picks the browser's language from the keys of window.I18N, so adding the two dictionaries in installer/i18n.js is all it takes. Both are translated from the English, key for key: 54 keys each, with the same links and markup as the other nine. The "Pick your language" step said nine in every language and now says eleven, and so does the file header.

Why these two: they are the languages Tiger Studio already speaks and the device now does too, so someone flashing a board reads the page in the language they will read the box in.

This does not depend on #26 to work. Until #26 is merged the page offers two languages the firmware does not have yet, so the two are best merged together.

What you tested it on

Docs only, in the sense that nothing on the device changes. The page was served locally and opened in a browser: Russian and Dutch both render, the language menu lists the eleven languages and switching to Dutch through it works. The dictionaries were also loaded in Node: all eleven have the same 54 keys. bash scripts/verify.sh --quick passes except "generated files match their generator", which also fails on a clean main on the machine used.

Checklist

• One concern. A rename and a behaviour change in one diff cannot be reviewed.
• English — comments, identifiers, log messages.
• No credentials, keys or tokens added anywhere.
• Any hardware constant carries a comment saying what breaks without it. (n/a, no hardware constant touched)
• Docs updated if behaviour changed. (the language count in the page and in the file header)
• CHANGELOG.md updated for anything user-visible. (left to the release ritual)