Support for dark mode and/or themes

[michaelo]

As an increasingly amount of tools support either a predefined dark-palette theme, or general theming functionality, similar functionality would be nice in Gitspeak as well to ensure a consistent user experience for those of us who prefer such.

As a mac user it would be convenient for me if it detected the current OS state, but it's not important. A manual option (ala the VSCode solution would be sufficient).

Examples:

macOS: https://support.apple.com/en-in/HT208976 / https://developer.apple.com/documentation/appkit/supporting_dark_mode_in_your_interface
VSCode: https://code.visualstudio.com/docs/getstarted/themes
Hack for Slack: https://gist.github.com/a7madgamal/c2ce04ddae8520f426005e5ed28da8608

[kigiri]

Oh yes, the darkness

[somebee]

We're getting to this :) First rolling out a big update for issues next week :)