Docs: Rework README.md for improved readability

[CyberForgeEx]

This commit completely replaces the previous README.md. The new version contains the same information but has been redesigned for a more modern and readable aesthetic. It includes new formatting, improved structure, and a better visual flow.

[a4lg]

I cannot let README to be removed since it's a part of standard GNU Automake-based packaging (where the file README is required) but formatting seems great. So,

1. If you change the contents of README (without renaming from README to README.md), I can accept.
2. I consider possibilities changing the packaging style (to accept README.md or similar).