Replace feather icons with Lucide

[SplittyDev]

Motivation

Feather Icons are abandoned and there are some issues with it.
Lucide is a commuity-maintained fork of Feather: https://lucide.dev.

TODO

• Lucide is ISC licensed. Check license compatibility with MIT.
• Check whether Lucide has significantly changed any of the base icons of feather.
• Alias lucide-* icons to feather-* (or just keep feather entirely?) to prevent breakage