Add an editor window color project setting

[Calinou]

This can be used to distinguish projects more easily, which is especially helpful when working on multiple projects at the same time.

The current coloring is a proof of concept. It does the job, but it's not that pretty. It'd be ideal if we could change the window border colors, but this requires us to implement client-side decorations first. (In other words, disabling the system-provided window borders and adding our own.)

This feature is inspired by the Visual Studio Code add-on Peacock.

Preview

[bruvzg]

The current coloring is a proof of concept. It does the job, but it's not that pretty. It'd be ideal if we could change the window border colors, but this requires us to implement client-side decorations first. (In other words, disabling the system-provided window borders and adding our own.)

There is PR for implementing custom window decorations - #23972, but it's not updated for the long time and had some issues last time I have tested it.

[aaronfranke]

@Calinou Is this still desired? If so, it needs to be rebased on the latest master branch.

[Calinou]

@aaronfranke Yes, but it probably needs to be redone to make use of client-side decorations once we implement those. In other words, we have to replace the system-provided window borders with our own.

[aaronfranke]

Marking as Draft because we should wait to see what happens with client-side window decoration support.

[akien-mga]

We discussed this in a PR review meeting and we don't really see much need for it. This should probably be moved to a proposal so the community can properly discuss and propose use cases where they would really use this. Otherwise adding a project settings for this seems niche enough that most users wouldn't ever find it and use it.

[beedell-roke]

This should be the job of the WM.