[CR] feat: iOS build

[sonphantrung]

Summary

None

Purpose of change

1. I want to play DDA on my iPhone
2. The ones provided on the App Store are outdated ~~and I can't afford as I'm broke~~
3. I want to have an easier way of compiling iOS builds

Describe the solution

This is a sequel of @smileynet's #61550 (attribution will be added later). Additionally:

• I have fixed some "angled" includes
• I aimed for feature parity with Android. To achieve this, I utilized Swift's fairly new C++ interop feature for exposing vars to existing code

Describe alternatives you've considered

Play on PC 😢

Testing

Additional context

Compared to compiling Mindustry/Shattered Pixel Dungeon, this thing is far tougher for a person not having a Mac like me. Any helps are appreciated!