add catppuccin, tokyo night, kanagawa, moonfly, nightfly and oxocarbon themes

[varbhat]

Add themes and color palettes from:

1. https://github.com/catppuccin/catppuccin
2. https://github.com/enkia/tokyo-night-vscode-theme
3. https://github.com/rebelot/kanagawa.nvim
4. https://github.com/bluz71/vim-moonfly-colors
5. https://github.com/bluz71/vim-nightfly-colors
6. https://github.com/nyoom-engineering/oxocarbon.nvim

Continuation of #2170

CC: @hecrj

[hecrj]

Awesome! Thanks 🎉