Resolve "Expandable folders for environments"

What does this MR do?

Adds back expandable folders functionality with new design.

When a folder is clicked we make a request to the server for the first 3 environments.

We render the response as a tree view and a button to allow the user to navigate to the folder's view with all the environments.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [ ] Documentation created/updated
• [ ] API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #28732 (closed)