Docs: Update project title, improve Phi-3 Cookbook case study, and README

[skytin1004]

Purpose

This PR updates the project title to emphasize the effortless translation of project documentation and enhances the Phi-3 Cookbook case study to provide a clearer understanding of the translation process. It also improves the README

Description

• Updated the project title to focus on effortless multilingual project documentation translation.
• Improved the case study of the Phi-3 Cookbook to better illustrate the Co-op Translator workflow.
• Replaced images in the README to visually reflect the translation folder structure and process.

These changes are necessary to clearly communicate the capabilities of Co-op Translator, especially its ability to automate translation for images, Markdown files, and multilingual documentation.

Related Issue

N/A

Does this introduce a breaking change?

When developers merge from main and run the server, azd up, or azd deploy, will this produce an error?
If you're not sure, try it out on an old environment.

• Yes
• No

Type of change

• Bugfix
• Feature
• Code style update (e.g., formatting, local variables)
• Refactoring (no functional or API changes)
• Documentation content changes
• Other... Please describe:

Checklist

Before submitting your pull request, please confirm the following:

• I have thoroughly tested my changes: I confirm that I have run the code and manually tested all affected areas.
• All existing tests pass: I have run all tests and confirmed that nothing is broken.
• I have added new tests (if applicable): I have written tests that cover the new functionality introduced by my code changes.
• I have followed the Co-op Translator coding conventions: My code adheres to the style guide and coding conventions outlined in the repository.
• I have documented my changes (if applicable): I have updated the documentation to reflect the changes where necessary.

Additional context