refactor!: switch to whiskers as theme engine

[sgoudham]

This PR starts the process for moving away from the deno build system and into catppuccin/whiskers.

TODO:

• [ ] Verify that delta is kept to a minimum between old and new hex codes
• [ ] Implement ui.theme.json
• [ ] Update contributing documentation to mention whiskers instead of deno
• [ ] Update intellij tasks to run whiskers instead of deno
• [ ] Update CI/CD to use whiskers instead of deno