Add color to `Language` model

[MizukiTemma]

Motivation

Page access statistics will bring higher understandability if each language has a certain fixed color regardless of which region it is. Currently languages receive a color in the order, which means:

If Color order: Red, Yellow, Green, White Region1 has: German, English, Arabic Region2 has: German, Arabic, Chinese

Then Region1: German-Red, English-Yellow, Arabic-Green Region2: German-Red, Arabic-Yellow, Chinese-Green

What we want is, for example: German-Red, English-Yellow, Arabic-Green, Chinese-White in all regions.

Proposed Solution

Add a color field to the language model, like color in POI category

Alternatives

User Story

Additional Context

This must be implemented before #1097

Design Requirements

Which colors should be in the choice, will come from @hauf-toni

[dkehne]

Good idea, i will move it to Q1/2024 because it can wait some more weeks.

[hauf-toni]

once you are ready to implement this, you can find my color suggestion in this file 🔴🔵🟣

[dkehne]

moved to 24Q3 because page based statistics moved as well.

[lunars97]

can I try to work on this ticket? Would that be fine?