Feature request: light/dark mode switch, themes

[edgar-ragde]

1. Add a light/dark mode switch.
2. Add a way to theme the app, no need for anything fancy, just text configuration files you can drop into some folder.

Generally I prefer dark mode, but because I have mild vision problems, dark mode has to be very specifically themed, so for some apps light mode is preferable.

Now on themes.
I see you're using a similar colour scheme to NewPipe. Few problems with it:
• OLED screens. Red can and will cause a burn-in.
• Contrast between dark and red is too harsh on my eyes. I suggest picking a dark mode colour scheme similar to GitHub, pleasant backgrounds and font colours, very easy on the eyes.
I think you can keep red highlights for text and icons, but that top bar has to be changed to some dark shade of grey.