Integrate something akin to CPStyling globally

[WSSDude]

Premise is to have look which feels more like CP77 style and to give mods and users ability to more easily change themes.

Mods could define themes for themselves, users could change default theme, etc.

All would be nice and dandy.

Issue for progress tracking.

• [ ] Custom themes in JSON (ideally not just colors for things, but complete themes controling custom widgets per type)
• [ ] Mods can use and define custom themes

[WSSDude]

Made #716 for UI rework effort tracking

[WSSDude]

Actually, this will probably be a bit bigger task... Gonna reopen this and track it here...