[Adjustment][Van] CLI Guide and Project Setup Modifications

[vansymph]

What does this PR do?

• Modify CLI guide documents
• Change node version to 18-lts
• Transfer FORK.md file to a new location

Why did you choose this solution?

• To align with the recommended setups in the readme
• Organize documentation for better accessibility

What is the dependency graph of the changes?

• Changes in node version may affect the project's build system
• Documentation improvements do not introduce dependencies

How to test/verify?

• Check CLI guide for completeness after changes
• Ensure node version update does not break existing functionalities

Related ticket url:

[symphdevtools]

Hi! I'm generating PR title and description for you and will automatically apply it to your PR. I'll react 🚀 to this comment when done. Just sit back and chill!

When you have new changes to this PR and you want to regenerate the title and PR description, just comment churva!

Let me know if something is not working well, e.g.:

• Some parts of the title and description weren't preserved when generating title and description
• Disappearing screenshots or links
• Etc.

Thanks!

(RIP hatdog)