Add modern Catppuccin themes

[kntng]

Description

Adds the new Catppuccin themes introduced in 2022 (see https://github.com/catppuccin/catppuccin/releases/tag/v0.2.0).

There are now 4 different themes: Latte (light), Frappe (dark), Macchiato (dark), and Mocha (dark) as showcased below.

Latte

Frappe

Macchiato

Mocha

Type of change

• [x] New feature (non-breaking change which adds functionality)
• [x] This change requires a documentation update

How Has This Been Tested?

• [x] Update themes.js and reload

Test Configuration:

• MacOS Sonoma 14.3
• yabai-v6.0.7
• Übersicht version 1.6 (82)

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] My changes generate no new warnings

Changes to make to the documentation

Add to list of themes.

[kntng]

I have left the old catppuccin theme intact (not sure if I should remove it).

[Jean-Tinland]

This is really neat, thanks! I renamed the old theme but I would prefer keep it for better retro-compatibility and not force cosmetics changes on anyone :)