Enhance metadata.json with multilingual support

[elig-45]

Updated metadata to include multilingual descriptions and additional fields.

This pull request updates the metadata for the Editable Author Select item to improve multilingual support and modernize field naming conventions. The most important changes are grouped below:

Metadata structure improvements:

• Renamed several fields for consistency and clarity, such as changing releaseDate to release_date, downloadURL to download_url, and adding new fields like price_usd, demo_url, and information_url.
• Removed personal author information fields (author, email, website, authorWebsite) and replaced them with author_username.

Multilingual enhancements:

• Added localized description and features fields for French (_fr), German (_de), Spanish (_es), and Russian (_ru) to support multiple languages.
• Updated the main description to be clearer and more concise, emphasizing administrator functionality and multilingual support.