Add user specific color setting for languages

[MizukiTemma]

Motivation

We have introduced a centralised language color assignment system which provides configuarable but inter-regionally same color-language combinations (see #2390 and #2715) to improve understandability of graphs in the statistics. However, it is not easy for everyone to distinguish all the colors each another, as we have already many languages and new ones are comming (see the conversatio in #2858).

Proposed Solution

Add a setting section where each user can configure a color for each language.

⚠️Language-color combinations which are saved by this setting should be valid and available only for the user who set it. Otherwise it contradicts to the original motivation of introducing inter-regionally fixed color-language combinations.

💡Show only languages that are relevant to the user in the setting? For region users only the languages that are used in the region, for admin users all languages?

Alternatives

Leave it as it is.

User Story

Additional Context

Design Requirements

• where to implement the setting section
• How it should look like (color picker was suggested in Add additional language colors #2858)

[PeterNerlich]

I'm having a diffuse but strong feeling that this is not the correct way to address the underlying issue. I think the colors should either be set in stone globally/regionally or be automatically calculated per region for optimal perceptual distribution, maximizing the contrast between all possible pairs of languages.

If we are at a point where adding more colors would make them too similar to each other, why not take a page out of the map designers book and augment our colors by patterns (diagonal stripes, polka dots etc.)?

I have not followed the discussion, but what happened to associations by country flag? It should be usable for quite a sizeable portion of countries, though does become difficult when flags are too similar and even problematic when they are flat out bad by having too much essential detail, so I see that it is not a complete solution.

[JoeyStk]

I think this is a question for the PO in collaboration with what the UX/UI team recommends :)

[jarlhengstmengel]

Problem country flags would be that the colors are used on in the statistics as colors in the charts

[MizukiTemma]

An idea from the issue grooming on 29.09

• We do not rocommend user-defined color-language setting.
• We recommend to add other visual design to destinguish colors, like dots, or breaked/not-breaked lines.