feat: reorg front page, config and readme

[juanpicado]

This pull request refactors the Verdaccio website's configuration and documentation to improve internationalization (i18n) support, centralize external URLs and credentials, and clean up unused testimonial components. The i18n filtering logic is now more robust, with clearer progress thresholds and logging, and the configuration is more maintainable due to the use of constants for external resources. Additionally, testimonial-related components and styles have been removed.

Internationalization (i18n) improvements:

• Refactored locale filtering in docusaurus.config.js to exclude languages below a minimum translation progress threshold (80%), with improved logging and mapping between Docusaurus and Crowdin locale codes. Locale labels now show translation progress dynamically. [1] [2] [3] [4]
• Updated README.md to document translation support, locale filtering logic, and instructions for adding/updating locales. [1] [2]

Configuration and maintainability:

• Centralized external URLs, credentials, and analytics IDs as constants in docusaurus.config.js, improving maintainability and consistency throughout the config. [1] [2] [3] [4] [5]

Component and style cleanup:

• Removed unused testimonial components: Testimonials.tsx, Testimonials.module.scss, and TwitterCarrousel.module.scss. [1] [2] [3]

These changes make the website easier to maintain, more transparent for contributors, and ensure only sufficiently translated locales are included in builds.