Refactor: Simplify theme and update README

This commit refactors the app's theme by removing the unused `Color.kt` file and the predefined `DarkColorScheme` and `LightColorScheme` from `Theme.kt`. Dynamic color schemes are now solely used.

The `README.md` has been significantly updated to provide a more comprehensive overview of the project, including:
- A detailed project description.
- Sections for Features, Built With, Getting Started, Available Components & Examples, and Screenshots placeholder.
- Enhanced Contributing guidelines.
- Added a "Find this repository useful?" section.
- Updated the License section to use the Apache License 2.0.