Upda te/collapsible menu html

[ajoju]

I have done the organization to the code to make it cleaner and more structured, used a consistent style for the links, used a better way to handle the submenus, used a proper CSS framework to style the menu.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as
  expected)
• Documentation (update or new)

How Has This Been Tested?

After saving the new code in a new branch, I opened up a new terminal in VS code and in a new gitbash, ran "docker compose build" and it built successfully. And tested the website in chrome in Google chrome, and it was running successfully.

Testing Checklist:

Tested in latest Chrome (through docker build)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have requested a review from ... on the Pull Request