Set up internationalization infrastructure and update dependencies along the way

[julienrf]

• Update our internal dependencies
• Set up an internationalization infrastructure based on the inlang stack
• Add French translation
• Document how to contribute translations
• Rename back “XC flying potential” to “thermal quality”
• Fix a couple of memory leak issues

[julienrf]

Deployed on https://soarwrf1.soaringmeteo.org/v2, here is a screencast:

Screencast.from.20-02-2024.17.56.23.webm

[julienrf]

The messages are loaded on-demand depending on the user selected language.

Currently, loading the website requires downloading 5 JavaScript files totaling 494 kB (162 kB compressed).

With this change, loading the website requires downloading 6 JavaScript files totaling 519 kB (172 kB compressed). Each language file weighs about 20 kB (7 kB compressed).

[Boran]

Excellent, I looked at the Screencast, the doc in the pull request. I cannot really say much about the code, looks clean

One thing, is the default English, or could it be inherited from the browser? People who have a French navigator probably want the site in FR.

When it is merged. I cam add a text or too in German, and ask some of out German speaking donors to contribute?

[julienrf]

One thing, is the default English, or could it be inherited from the browser? People who have a French navigator probably want the site in FR.

When I looked at that a couple of weeks ago I thought it was a bit complicated and unreliable to auto-detect the user's preferred language, but I had another look this morning and I think something is doable, I will give it a try!

[julienrf]

I updated the PR based on your feedback: the menu option names in French are not capitalized anymore, and we detect the user lang based on their browser configuration. I’ve redeployed it on soarwrf1.