feat: add changelog and update footer links

[aru-amedeo]

Description

This pull request introduces the following changes:

1. Changelog:

   • Added a CHANGELOG.md file to document all notable changes to the project.
   • The changelog follows the Keep a Changelog format and adheres to Semantic Versioning.

2. Footer Updates:

   • Updated the footer to include links similar to those on the Aruba Cloud SDK Go page:
     • Docs: Links to "Getting Started" and "API Reference".
     • Community: Link to the GitHub repository.
     • More: Link to the changelog.

3. Navbar:

   • Added a GitHub link to the top-right of the navbar, pointing to the repository: https://github.com/Arubacloud/api.

Motivation

These changes aim to improve the documentation and navigation experience for users by:

• Providing a clear changelog for tracking updates.
• Enhancing the footer with useful links for quick access to important resources.
• Adding a direct link to the GitHub repository for better community engagement.

Testing

• Verified that the new footer links are displayed correctly.
• Confirmed that the GitHub link in the navbar works as expected.