The PR aims to improve the README usability for new users as well as
developers looking to go in depth.

Key improvements include:

- **Structure & Navigation:**
  - Introduces a detailed Table of Contents for easier navigation.
  - Improved overall organization of sections.
- **Content:**
  - Expanded "What is Redis?" with section for "Key use cases"
  - Expanded "Why choose Redis?" section
- New "Getting started" section, including Redis starter projects and
ordering of sections based on desired use for new users
- Changes to "Redis data types, processing engines, and capabilities"
section for better readability and consistency
  - Formatting markdown blocks to specify language