Enhancing The Update Framework (Python - TUF) README

[shubhusion]

Description of the changes being introduced by the pull request:

1. Table of Contents: Added a Table of Contents to improve navigation and accessibility within the README.

2. Logo Color: Changed the logo color from black to white to enhance visibility and improve the overall aesthetic of the document.

3. Additional Badges: Included additional badges to highlight key aspects such as version, license, tech-stack, and community support, providing users with quick access to essential information.

4. Back to Top Button: Added a "Back to Top" button at the bottom of the README to facilitate easy navigation within the document.

5. Installation Section: Added an Installation section to provide users with clear guidance on how to install the software.

6. Contact Section Enhancement: Separated the Mailing List and CNCF Slack links for better readability and organization within the Contact section.

7. CNCF Logo Addition: Added the CNCF logo at the bottom of the README to acknowledge the project's affiliation with the Cloud Native Computing Foundation.

Before:

After:

Fixes #2654

Reviewers:

@trishankatdatadog @JustinCappos