Carthage - bye, SPM - hello! 👋🏻👋🏾👋🏿

Carthage removed completely! 💀
SPM added! 🎉✨

Also a lot of changes:

• Minimum supported target is 12.0 now; 🤠
• Removed separate project for Example.
• Updated swiftlint due to deprecated rule and Pods folder.
• Added Example target to the root project.
• Pods now in root project.
• Added Launch screen.
• Sorted files in project.
• Fixed some swiftlint issues.

Thx to @NikKovIos, @RomanTysiachnik, @sahbazali 🤌