Add Random ASCII Banner Collection

[JamesTsetsekas]

🎨 ASCII Art Extravaganza - Random Banner Collection

What's New?

Tired of seeing the same banner every time you start BitChat? Well, no more! This PR introduces a delightful collection of 8 unique ASCII banners that randomly rotate on startup.

🌈 Banner Styles Included:

• Original LaTeX - The classic green banner (kept for nostalgia)
• Big Block Letters - Bold Unicode blocks in magenta
• Graffiti Style - Chunky street art vibes in red
• Slant Style - Sleek angled design in blue
• ASCII Art - Clean minimalist orange text
• Modern Minimal - Boxed design with cyan accents
• Cyberpunk - Retro terminal aesthetic in bright green
• Matrix Style - High-tech Unicode blocks in matrix green

✨ Features:

• 🎲 Random Selection - Different banner every startup
• 🎨 Colorful Variety - Each banner has its own color scheme
• 🏷️ Consistent Branding - All clearly display "BitChat"
• 📦 Zero Dependencies - Uses existing random module
• 🔧 Easy Maintenance - Simple lambda-based architecture

Why This Matters:

Because starting your decentralized chat client should feel like opening a surprise gift every time! 🎁

Life's too short for boring terminal banners. Let's make every startup a little more delightful! ✨

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Making BitChat more fun, one random banner at a time 🚀

[o-murphy]

@JamesTsetsekas I think it's relative to #14

Before theming and prettyfying first think should be fine is merged #7 and second - resolved issues with android app compatibility, also there are removed channels funcs from iOS api