Allow per-project Godot Editor themes

[azur-wolve]

have a project setting that allows to set per-project editor themes

also the theme settings present in Editor Settings → Interface → Theme (icons_and_font_color, base_color, accent_color, contrast, etc) , with a checkbox to prioritize the ones in project settings

could be placed on Project Settings → GUI → Editor

[Calinou]

This is addressed by #1480.

However, I think this is better addressed by something like godotengine/godot#34528. It's focused on making it easy to quickly distinguish multiple projects, especially when you have multiple Godot instances open at the same time.

I use Peacock in Visual Studio Code and it works pretty well for this use case. Note that it does not save the color to version control, but to project-specific metadata instead (i.e. in Godot, this would be in .godot/ in the project folder). This allows users to choose the color they want on a per-project basis. If this doesn't suffice, we could also have a project-suggested color as a project setting that would be used by default.

[Mickeon]

This would also be possible, more generally, with godotengine/godot#69012